\verb is a very peculiar command in LaTeX and this peculiarity consists in the fact that it may not appear in the argument of another command. In your example it is in the optional argument to \begin{lstlisting} and this is disallowed (because of very good reasons).
Actually \verb is necessary only when characters special for (La)TeX are needed: # $ % ^ & { } _ \. When none of these character is needed, one can use \texttt{myverb material} with the same result as that given by \verb.
However, this doesn't solve the problem of grepping through your files for finding all \verb. You can do
\protected\def\psverb#1{\def\innerpsverb##1#1{\texttt{##1}}
and the example would become
\documentclass{article}
\usepackage{listings}
\protected\def\psverb#1{\def\innerpsverb##1#1{\texttt{##1}}\innerpsverb}
\begin{document}
\begin{lstlisting}[language=Perl,caption={text {\psverb+myverb+} some more text}]
...
\end{lstlisting}
\end{document}
Grepping for \verb or \psverb should be quite easy.
\verbbecause what you denote withmyverbhas special characters in it? If it hasn't, then\texttt{myverb}does the same. – egreg Sep 12 '12 at 10:45grepthrough my tex files and I now won't collect allverbs with this. But that is a minor setback. If there is no real solution, please post your comment as an answer, so I can accept it. – javex Sep 12 '12 at 10:53