I had the same problem for a week straight. After about 10-15 re-installs, I gave up because I was so frustrated. Then I decided to give it one last shot and tried the over-the-air install and it worked. So I know this isnt the best advice but keep installing/re-installing... it'll eventually work.
i tried JV's settings and still no go. Am i missing something? I am on OS 4.0. I have an unlimited data plan, so i can surf and use e-mail as much as i want for like $50 bucks. Am i missing anything else? Do i need to call Cingular and have them do anything?