No cleveref in beamer?

Question

I am trying to get a math beamer presentation to work and it seems that cleveref is causing problems. The MWE below gives the error

Paragraph ended before \@ynthm was complete

In the documentation of cleveref, one finds the following remark:

The beamer document class rededefines the \label command in a particularly devious way that breaks cleveref's optional argument to that command.

What optional argument? Does that mean that cleveref and beamer are simply incompatible? Is there any way around that problem?

MWE:

\documentclass{beamer}

\makeatletter
\let\th@plain\relax
\makeatother

\usepackage{ntheorem}
\usepackage{cleveref}

\theoremstyle{plain}

\newtheorem{MainThm}{Main Theorem}

\crefname{MainThm}{Main Theorem}{Main Theorems}

\mode<presentation>{\usetheme{Frankfurt}}

\begin{document}
\begin{frame}{Test}
    \begin{MainThm}
        blabla
    \end{MainThm}
\end{frame}
\end{document}

Answer 1

cleveref redefined \label to now take an optional argument that overrides the cleveref type. However, if you don't use this optional argument, then you're fine.

Switch the load order between cleveref and ntheorem.

\documentclass{beamer}

\let\Tiny\tiny% http://tex.stackexchange.com/q/58087/5764
\makeatletter
\let\th@plain\relax
\makeatother

\usepackage{cleveref}
\usepackage{ntheorem}

\theoremstyle{plain}
\newtheorem{MainThm}{Main Theorem}
\crefname{MainThm}{Main Theorem}{Main Theorems}

\mode<presentation>{\usetheme{Frankfurt}}

\begin{document}

\begin{frame}{Test}
  See~\cref{thm:mytheorem}.
  \begin{MainThm}\label{thm:mytheorem}
    blabla
  \end{MainThm}
\end{frame}

\end{document}