I have come across numerous post saying the google maps 2.3.2 doesn't work on blackberry OS 4.5.
Today I upgraded my phone to 4.5 and then I installed google maps 2.3.2 and it works. The way to go about is before you download google maps over the air (OTA) on the phone set the permissions to Allow to all and then press download. The google map downloads and then installs on the phone. After you get the message sucessfully installed restart the phone and Voila google maps work just fine on OS 4.5.