CGI::Carp is always the first step. However, "use CGI::Carp qw(fatalsToBrowser);" occasionally does not provide everything you need to debug your script. If you have access to your servers error log, typing (in Linux, for example) tail error.log (or whatever your error log filename is, assuming you're in the log directory) will print out the last few lines of that log and may give you additional information.

If you are using the CGI module, you can try instantiating a CGI object and running the script from the command line.

#!/usr/bin/perl -wT
use strict;
use CGI;

my $query = new CGI;
[download]

When running the script from the command line, it will as you to enter name/value pairs in the format name=value. Enter all appropriate name/value pairs and hit cntl-d (cntl-z on Win32 systems) and the script will continue execution. Any errors will be directed to your terminal window.

Cheers, Curtis