This has nothing to do with Perl. First get tinymce to work with a static HTML page, then try to get it to work with Perl.

To attack the problem from the other side, get a plain CGI script that has nothing to do with TinyMCE, and see whether that works.

If you already got both things to work, it's a matter of reading the TinyMCE documentation to find out what requests it sends to your script, and then a matter of looking at the webserver error log as to what goes wrong.

This site is about problems with Perl, not problems with Javascript and HTML, so you're much more likely to find help with the second and third part of solving the problem. Where exactly do you have problems?

TinyMCE is JS, it doesn't need to be a server side executable or in your cgi-bin. If you're having a problem with CGI code you're writing to receive/send with TinyMCE, you'll get better help if you'd post the actual problem; code, errors, etc. Here is just one of the many jumping off places for troubleshooting: Troubleshooting Perl CGI scripts.

site:perlmonks.org CGI javascript

http://search.cpan.org/dist/CGI.pm/MANIFEST

http://cpansearch.perl.org/src/LDS/CGI.pm-3.49/examples/javascript.cgi