What it means is that your program uses a module named "javascript.pm" and that it isn't available on the server that your script is running. When you say "it worked for me and him" do you mean it worked on your server, but when others started using it (on other servers) it breaks? That's not a surprise as I don't think URI::javascript is part of a standard Perl install which means everyone who wants to use your program will also need that module installed.