Like for the first week i had my phone, (i had already done the new software update) it would load the messenger you are talking about. I had called tmobile on this issue, but they could help me. So i let it go. then like a few days later, i thought iwould try it, and there it was working an everything was ok.
Also, if you download the aftermarket yahoo messenger on your phone(it should be in your internet bookmarks on your phone its the blackberry help, it is somewhere in there), anyways back to the point, if you download it, it won't use your text messages like if you use the embedded messengers that come on the phone. That is what i was told by from tmobile The embedded messengers use your text messages and the after market yahoo messenger doesn't