Error message because of eqnarray, footnotes, tables or caption?

Question

I know this is not a minimal example, but I have to have this much code, in order to create my error. I had this error already several times and I cannot get rid of it?! I don't know where the problem is. Something is not correct with align and footnotes, at least this seems to be the reason for me?

Here is my code:

\documentclass[a4paper, 
        12pt,                               
        bibliography=totoc,     
        index=totoc,    
        abstracton,     
        headsepline,    
        ]{scrreprt}
\usepackage{latexsym}           
\usepackage[latin1]{inputenc}   
\usepackage[ngerman,english]{babel}   
\usepackage{amsmath} 
\usepackage{subfig}     
\usepackage{float}      
\usepackage{graphicx}       
\usepackage{rotating}   
\usepackage{mathrsfs}
\usepackage{eurosym,bm,amsmath,amssymb,verbatim}
\usepackage{listings}
\usepackage[T1]{fontenc}
\usepackage{setspace}
\usepackage [round,authoryear] {natbib}
\usepackage{amsthm}
\usepackage{graphicx,eso-pic,lipsum}
\usepackage{url}
\usepackage{tikz}
\usepackage{tocstyle}
\usetocstyle{allwithdot} 
\usepackage[bookmarksopen,hyperfootnotes=false,pdftitle=test, pdfauthor=test,pdfsubject=test]{hyperref}
\usepackage{fancyhdr}
\usepackage{listings} 
\usepackage{remreset} 
\makeatletter
\@removefromreset{footnote}{chapter}
\makeatother
\usepackage{dblfnote} 
\usepackage{booktabs} 
\KOMAoption{footnotes}{multiple} 
\usepackage[top=2cm,bottom=2cm]{geometry}
 \usepackage{cleveref} 


\definecolor{headercolor}{rgb}{0,0,0}
\definecolor{white2}{rgb}{255,255,255}



\begin{document}                    



\begin{titlepage}
test

\end{titlepage}

\onehalfspacing 

\fancypagestyle{plain}{%
  %% Clear all headers and footers
  \fancyhf{}
\fancyhead[L]{\hspace{5.5mm}\textcolor{white2}{\leftmark}\\ \text{ }\textcolor{white2}{\hspace{0.4cm}\rightmark}\hfill\textcolor{white2}{}\hspace{2mm}}
\renewcommand{\headrule}{\vspace{-\headheight}\textcolor{white2}{\vrule height \headheight width 2pt\relax\rule{\textwidth}{2pt}\vrule height \headheight width 2pt\relax}}
\fancyfoot[C]{-\thepage -}
}

\pagestyle{fancy}
\fancyhf{}
%\renewcommand{\chaptername}{}
\renewcommand{\chaptermark}[1]{%
\markboth{\MakeUppercase{\thechapter. \hspace{1.5mm} \  #1}}{}}


\fancyhead[L]{\hspace{5.5mm}\textcolor{headercolor}{\leftmark}\\ \text{ }\textcolor{headercolor}{\hspace{0.4cm}\rightmark}\hfill\textcolor{headercolor}{}\hspace{2mm}}
\renewcommand{\headrule}{\vspace{-\headheight}\textcolor{headercolor}{\vrule height \headheight width 2pt\relax\rule{\textwidth}{2pt}\vrule height \headheight width 2pt\relax}}
\fancyfoot[C]{-\thepage -}

\begin{appendix}
\clearpage
\chapter{Appendix}


\subsection[Text]{Text}
\label{parameterestimation}
text texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext text\footnote{\citep[pp. 7-8]{Author1:1993}}. text texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext text\footnote{\citep[para. 4]{Author2:2002}}.

\subsubsection[Textn]{Text}
text texttext texttext texttext texttext texttext texttext texttext texttext texttext text\footnote{\citep[para. 4] {Hazewinkel:2002}}.
\paragraph{ML}\footnote{Text \citep[p. 12-13]{A:2006}}
text texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext text
\begin{align*}
54=54
\end{align*}
and the log likelihood by
\begin{align*}
54=54
\end{align*}
vtext texttext texttext texttext texttext texttext text
\begin{align*}
54=54
\end{align*}
text texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext text\footnote{\citep[p. 3] {Author1:2006} text texttext text}. text texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext text\footnote{\citep[para. Details] {Author2}}. text texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext text\footnote{\citep[para. Details] {RDocumentationoptim}} text texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext text\footnote{\citep[para. Details] {RDocumentationfitdistr}}). \\ \newline
text texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext text\footnote{\citep[p. 53] {Ruppert:2004}}:
\begin{align*}
54 = 45
\end{align*}
text texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext texttext text\footnote{\citep[p. 7] {Steenbergen:2006}}:

  \end{appendix}



\clearpage
\fancyhead[L]{\hspace{4mm}\textcolor{headercolor}{}\text{ }\textcolor{headercolor}{\rightmark}\hfill\textcolor{headercolor}{}\hspace{2mm}}
\renewcommand{\headrule}{\vspace{-\headheight}\textcolor{headercolor}{\vrule height \headheight width 2pt\relax\rule{\textwidth}{2pt}\vrule height \headheight width 2pt\relax}}
\fancyfoot[C]{-\thepage -}

\end{document}  

I get the error:

! Improper \halign inside $$'s. \halign

This is NOT due to a specific align environment, e.g. a typo error in an align environment, I have this problem throughout my complete thesis!

Answer 1

This is not an answer, but ... I condensed your code to

\documentclass[12pt]{scrreprt}
\usepackage{setspace}
\usepackage{dblfnote}
\usepackage{booktabs}

%------------------------------------------------------------------------

\textheight245mm
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{document}
\onehalfspacing

text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text
\footnote{text}
\begin{table}[h]
\begin{tabular}{llr}
\toprule
a & b & c \\
a & b & c \\
a & b & c \\
a & b & c \\
a & b & c \\
a & b & c \\
a & b & c \\
\bottomrule
\end{tabular}
\end{table}
test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text 
text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text 
text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test 
test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text 
text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text 
text test test test test text text text test test test test 
text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text.
\subsection{Sec}

test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text
\footnote{text}
\footnote{text}
\begin{eqnarray}
a & = & b
\end{eqnarray}
test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text\footnote{text} text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text test test test test text text text.
\footnote{text}
\begin{eqnarray}
a & = & b
\end{eqnarray}
\end{document}

which looks quite innocent apart from setting the \textheight manually. Changing any detail makes the error go away, so I guess something fishy is going on here. I provide this for others as a better starting point.

Answer 2

This is not an complete answer, but it contains a needed MWE and some notes. Also, note that others who land here because of that error message, may be instead interested to look at: Modifying \everydisplay causes the align* environment to stop working

Below is the MWE and some notes about it.

\documentclass{scrreprt}
\usepackage{dblfnote}
\begin{document}
  This seems to be a irrelevant\footnote{footnote one}

  \vspace*{20cm}

  \hspace*{14cm} text text\footnote{footnote two}\footnote{footnote three}
\begin{eqnarray}
a & = & b
\end{eqnarray}
\end{document}

The above code produces the error. My guess is that it is related to a line break near to the end of a page, the package dblfnote and the eqnarray environment. Let us see.

Replacing "text text" by "xxxxxxxxxxx" the code will compile with no error, even for any other values of hspace. However, changing "text text" word that can be hyphenated, like "important", will lead to the error.

Changing \hspace*{14cm} to \hspace*{13cm} produces no error, even if we change the value of vspace to anything else (for large values, the text will not be displayed correctly, but LaTeX does no complain). On the other hand, keeping \hspace*{14cm} (or larger) and decreasing the \vspace value to \vspace*{20cm} will produces no error.

It is very puzzling...