Everything was going as planned. I sucessfully retro fitted a RNS-E unit into my A4 B7 and everything was working ok. I then removed the instrument cluster to make the final install, fitted the GPS antenna behind it and put everything back together.
Suddenly nothing works. The car won't start (it shuts down automatically), which of course is the biggest problem. The word SAFE is in the instrument display. I get warnings for everything from low oil to no coolant and the interior lights are acting all weird. The RNS-E still works, but not much else.
Can i do anything or do i need to tow it to the dealer?

Note: I don't have access to VAG-COM.
Note: I did the whole operation without disconnecting the battery.