Thanks for your quick reply Derby. The script does use LWP::UserAgent. Here is my stripped down test script:

use CGI qw/:standard/;
use CGI::Carp (fatalsToBrowser);
require LWP::UserAgent;
print header;
my $ua = LWP::UserAgent->new; 
my $url = 'http://google.com'; 
my $response = $ua->get($url); 
if ($response->is_success) {
     print $response->decoded_content;  # or whatever
}
else {
     die "failed: $url : ", $response->status_line;
}
[download]

So, it's dying w/ Status code 500. The server logs don't say much: "GET /scripts/prince/lwp_test.plx - 200 Mozilla/5.0+(compatible;+MSIE+10.0;+Windows+NT+6.1;+WOW64;+Trident/6.0;+EIE10;ENUSWOL)" I have run this script on two different servers, after the Perl upgrade on both, and I get the same error message.