Ah, but does it display OK in IE 8? Most other browsers may have an error on that or another line. But most other browsers won't tell you anything about it unless you ask them to. The default in IE 8 is to show most errors in the status bar.
Anyways, here's the line:
I found a hostbooter.com/_test/term.php page that uses the script and validate is not defined. As long as the page displays OK, you may remove that entire block of code (not just the highlighted). But there may be other errors. Firefox reports (when asked):
// VALIDATION REPLY FORM //
So once you remove the first block, this Line: 13 error or something else may show up in IE 8.
Error: $("#slider").jFlow is not a function
Source File: hostbooter.com/_test/js/custom.js