Ajaxify not working in Firefox

[salvatorious]

This plugin works very well (in Chrome) on a site I'm developing. In Firefox, however, ajax isn't firing at all. Is this a known issue with the plugin or could there be something else interfering with it?

Edit: I realize this is a vague question. Here's the error message I'm getting in Firebug.

-- Start Error --

ReferenceError: event is not defined
if ( event.which == 2 || event.metaKey ) { return true; }

-- End Error --