if you have firebug installed on Firefox, you'd possibly notice the actual errors?
most likely a javascript one.. there could be a conflict with one of the functions in mootools being named the same as one in ubb_js or even a shared variable name?
i use a similar js framework (prototype and scriptaculous) and there are no conflicts..
if you can possibly report what specific errors you are getting, it might be as simple as renaming somethings and changing a .tpl file.
