Entries in my KOMA-script TOC spread too close from the page numbers:

One solution is to use a short title and insert in it a line-break, but this is not an acceptable solution.
I am trying to modify the tocrmarge. Here are my attempts, but all compile with errors:
\makeatletter
% one and one only of the following
\renewcommand*{\settocfeature}{tocrmarge}{10em}
\renewcommand*\l@tocrmarge}{10em}
\renewcommand*{\settocfeature}{\setlength{\@tocrmarge}{10em}}
\makeatother
My understanding of LaTeX is not good enough. I need help to write correctly the command please.
EDIT: add a MWE (not so minimal in the preambul)
\documentclass[english,enlargefirstpage, full]{scrbook}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[paperwidth=148mm,paperheight=210mm]{geometry}
\geometry{verbose,tmargin=3cm,bmargin=3cm,lmargin=2.5cm,rmargin=3cm}
\usepackage{fancyhdr}
\pagestyle{fancy}
\setcounter{secnumdepth}{-2}
\setcounter{tocdepth}{1}
\usepackage{pifont}
\usepackage{textcomp}
\usepackage{fixltx2e}
\PassOptionsToPackage{normalem}{ulem}
\usepackage{ulem}
\makeatletter
\@ifundefined{lettrine}{\usepackage{lettrine}}{}
\@ifundefined{date}{}{\date{}}
\usepackage[english,frenchle]{babel}
\usepackage[nottoc,numbib]{tocbibind}
\renewcommand{\sectfont}{\normalfont\bfseries} %\slshape} %\rmfamily}
\makeatletter
\renewcommand*\l@chapter{\bprot@dottedtocline{1}{1.8em}{3.2em}}
\renewcommand*\l@section{\bprot@dottedtocline{1}{1.8em}{3.2em}}
\renewcommand*\l@subsection{\bprot@dottedtocline{3}{1.8em}{3.2em}}
\makeatother
\frenchspacing
\usepackage{hyphenat}
\hyphenpenalty=3500
\doublehyphendemerits=9000
\finalhyphendemerits=6000
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage[babel=true,kerning=french,protrusion=true,expansion=auto,spacing,tracking]{microtype}
\pretolerance=1500
\tolerance=2000
\setlength{\emergencystretch}{2em}
\AtBeginDocument{
\def\labelitemi{\Pisymbol{psy}{42}}
}
\makeatother
\usepackage{babel}
\begin{document}
\title{my book title}
\subtitle{my book subtitle}
\author{\textbf{myself}}
\maketitle
\frontmatter
\chapter{Before}
blublu
\tableofcontents{}
\newpage{}\mainmatter
\part{PROLOG}
\chapter{\emph{chapter 1}}
blabla
\chapter{\emph{chapter 2 title is very long and should look uggly}}
bloblo
\end{document}
And its result (not as uggly as in my real document):

EDIT: Here is the successful build log (in a pastbin, since otherwise I exceed the Stack Exchange 30,000 characters body limit.

\documentclass{...}and ending with\end{document}. – May 17 '14 at 09:26\section[shorttitle]{long title}? – May 17 '14 at 09:27