pending → closed
Please note that with jQuery 1.5, we introduced a major re-write of the ajax module which came with a number of rather large changes to how it works beneath the hood. It would appear that your JAX-RS service was making use of some of the older code, and may need to be updated to reflect how ajax works in the newer versions of jQuery core. Fundamentally, you should be able to use the same signatures but I strongly recommend reading up on http://api.jquery.com/jQuery.ajax/ to note what changes were made.
Because your ticket appears quite generic and you don't seem to have pinpointed what in ajax is breaking for you at the moment, it would be best if you could double check your code, go through the ajax docs and see if there are any minor changes you may need to make to it. You can always ask in the jQuery Forums for assistance with this if needed.
When/if you find that the ajax docs don't assist in helping you resolve this and you've managed to ascertain exactly whats breaking for you, please feel free to open up a new ticket with the reduced issue and a test case and we'll be happy to help further.