Yes, LWP::UserAgent was the ticket. This was the ideal solution that I was seeking:

 my $ua = LWP::UserAgent->new;
 my $response = $ua->get($url);
 if ($response->is_success){
    (good things happen) 
 } else {
     my $failmsg= ($response->status_line);
    (print the $failmsg)
    return;                           
 }
[download]

BUT, for this to work, the web based script, after being triggered by the get(), must return some response that is part of the HTTP protocol. I added this line to the top of the web based script:

print "Content-type: text/html\n\n";
[download]

Otherwise you receive a 500 Internal Server Error. Thanks again for the help!