It could be case sensitive. Have you entered the password and ID exactly how it is on the computer? If your password is with two capital letters then enter it exactly as it is. Exmaple of password: KiTten0 so enter in on your phone exactly as that password KiTten0.
I see this was posted a while ago, but I was having the same probem on my bb. Mine was set up so that when I went into Google Talk my username appeared and then I typed in my password. I found when I kept getting this message that if I erased the username and retyped it, then the password it worked most of the time. Perhaps it was just luck, but it seemed to work more often than not.