I solved the problem by placing a " $(document).ready(function(){" call in the file being loaded into the tab (using UI.TABS). Once I did this, and of course added th other necessary FORM plugin goodies) all worked fine.
I had thought that the file being loaded into the tab was included in the DOM (it shows in FireBug), but I guess it must be added after the creation of the tab interface. BTW: Really enjoying working with jQuery and friends. I had initially started the project I'm working on using Adobe's Spry. While all worked well, there seemed to be a lot more coding and overhead. And, knowing Adobe is quite profit-centered, was not comfortable using Spry for an open source project.