It's a good idea to keep the error_log open all the time in a dedicated terminal using tail -f:

panic% tail -f /home/httpd/httpd_perl/logs/error_log

or less -S:

panic% less -S /home/httpd/httpd_perl/logs/error_log

You can use whichever one you prefer (the latter allows you to navigate around the file, search, etc.). This will ensure that you see all the errors and warnings as they happen.

Another tip is to create a shell alias, to make it easier to execute the above commands. In a C-style shell, use:

panic% alias err "tail -f /home/httpd/httpd_perl/logs/error_log"

In a Bourne-style shell, use:

panic% alias err='tail -f /home/httpd/httpd_perl/logs/error_log'

From now on, in the shell you set the alias in, executing:

panic% err

will execute tail -f /home/httpd/httpd_perl/logs/error_log. If you are using a C-style shell, put the alias into your ~/.cshrc file or its equivalent. For setting this alias globally to all users, put it into /etc/csh.cshrc or similar. If you are using a Bourne-style shell, the corresponding files are usually ~/.bashrc and /etc/profile.