Welcome to BlackberryOS Woobie
The first thing is the new BBM 5.0 will not work on the .77 OS you will need to upgrade that OS. The good news is it sounds like you want to do that anyway
Here is a link to the latest OS for the 8330
4.5.0.160
Once you download that to your PC go ahead and install to the pc. Once installed
Navigate to C-program files-common files-research in motion- app loader and delete the vendor file -it will look like this
In the same folder (apploader) you will see laoder.exe double click that and install to your phone ---app loader looks like this
**Don't forget to back up your Phone and 3rd party apps before installing the new OS to your phone ***
If you have never backed up your 3rd party apps here is a video walk through to show you how
http://www.blackberryos.com/forums/h...lications.html
Once you have this new OS installed it will put the old BBM on your phone. Then you can proceed to install the new BBM 5.0
Just post if you have anymore questions or you get stuck somewhere.