2003 BMW 745

I just bought a 2003 BMW 745li when I bought it I was told it needed an alternator so I replaced it and then I found out that they had the wrong battery in the car so I replaced that then we reset the battery. Now I'm having issues with the transmission, the car runs perfect when its cold but as soon as the car warms up the transmission failsafe light comes on and then if you put the car in park it will no go back into gear. If you allow it to cool down everything is fine buy this repeats over and over any ideas as to what the problem may be would be greatly appreciated.
January 27, 2013.

Software updates are in order.

Dr. Hagerty
Feb 1, 2013.