Monks usually like to see the following info:
1. What is your OS?
2. Some CODE
3. What did you try?

Having said that... and without anything to look at, most of the CGI errors you seem to be talking about are because your form may not be returning anything or aren't being initialized and are undefined. Are you connecting to a Database or other module that is failing because your parameter list is incomplete? Who knows.... You need to supply more info... like what your code is doing.. which modules are you using? What version of Perl?
try use Warnings; and use Strict;

perldoc perldebug
I would suggest that you purchase the Camel and Llama Books on Perl by Merlyn and Perl's Author Larry Wall at ORE. These folks won't answer questions without some real effort on your part. :-(