There should be a link from somewhere on the Cingular website that offers a page for your blackberry BWC. That is definately the problem. Your Blackberry Web Client is full im sure. It only holds 10mb if im not mistaking. Once in there you should just be able to clean house.
Actually, I think I just found the link. https://webclient.blackberry.net/Web...ite=mycingular
There you should be able to get in. It is the email and password that you set up while configuring your handheld. Once in, clean out all of the stuff.