BMW X5 with serious issues

[Doonbugg]

Hi All, I have been trying to track down what is suddenly wrong with my 2005 X5 4.4. It cranks great, UNTIL you take it out on the road it runs great. The first thing to go is the transmission goes into failsafe mode. Then the dash lights all start coming on and flashing, Then the engines starts running very rough and will not run. When I tried to restart it it was a no go and everything ( including the headlights ) started flashing. I just cleared the computer and reset the dash a couple days ago. I dont know if this has anything to do with it but is was raining both times it did this. It is on the side of the road now and I am kinda out of ideas. Does anyone have any ?