Do you have a FastCGI daemon listening on port 2005? Your Perl application must be ready to handle FastCGI as well. My guess is that that's not the case. An example about how a FastCGI enabled Perl script looks like can be found
here. And don't forget to read the FastCGI section of the
CGI and FastCGI HOWTO.
FastCGI is not a simple switch-on thing. Unless you use PHP, which does all the fancy FastCGI stuff for you.