A. There are many different possibilities. If you have a problem, misconfiguration, or syntax error in your script, you will probably be able to find it by checking your error logs which can be found in your Control Panel.
Although this is generally caused by a problem within the script, many times it is caused by incorrect file permissions either on the script itself, or another file or directory used by the script. You should also verify that the script paths are set correctly.
You should verify that the first line of your script is the path to Perl, and that it is correct. It should be set to:
/usr/bin/perl
OR
/usr/bin/perl -w

You should also verify that the scripts were uploaded in the correct mode.

Another problem could be permissions of the file or directory. Your script permissions should be 755, or rwxr-xr-x.