I had some problems downloading ringtones with my 7100t. Itdidn't matter which version of OS I had, I tried 3 different versions directly from TMO's website. It didn't matter if i sync'd with a BES or used BWC. I looked through all settings I could find. I was able to download one or 2 here and there at various stages of testing, but it was not consistant at all.

I then decided to delete a service book relating to something that I don't use. I deleted the one related to the t-zones browsing or some such. I didn't note the exact title because I didn't think it would work, but for me it did.

Hope this helps someone else.