I think you may have to reinstall 2.5Xtreme and then install the 2.5.2 upgrade to revert back to 2.5.2. You can certainly try installing the 2.5.2 upgrade over your 3.1 install but I don't think it's going to work. One way to be sure is to create a backup image of your 3.1 OS and restore it to another drive. Then try installing the 2.5.2 upgrade to see if it will revert with no problems. If it works then you can try it on your original drive and possibly keep your existing recordings. If you're not concerned about saving any recordings then a fresh install would be your best bet.
Please don't PM me or any other members looking for personal assistance. You'll do better by posting (after you've exhausted the search feature, of course) and taking advantage of the collective expertise of the membership instead of a single individual that may or may not be able to help you. Thank you and enjoy your stay at DDB!