I can measure it myself if you can provide me with URLs to your resources and identify them in terms of which one is mod_CGI and which is mod_perl.
This is the mod_cgi one that works fine, no errors: http://shevek.kenyonhill.com/cgi/test.pl
This is the mod_perl one (same script) that generates the "20014:Error" in the error_log. Also, the page doesn't display correctly (it seems to erase itself):
http://shevek.kenyonhill.com/perl/test.pl
This is the contents of test.pl:
--- #!/usr/bin/perl $|=1; print "Content-Type: text/html\n\n"; print "hello world<P>"; # This line causes the error print ""; ---
Let me know if you need anything more.