Well if VCDS kicked you out, it didn't work properly hence the DEF error.
What s/w did you use the get the SKC out of the S4 cluster? VAG EEPROM programmer 1.19 is supposed to work the best (although still a bit buggy for some). Try following Cshuster's DIY on Audizine:
http://www.audizine.com/forum/showthread.php/658776-Color-DIS-S4-cluster-into-red-DIS-car?p=11451530&viewfull=1#post11451530That is the best I can do sorry. Never done the swap personally. I'm in Canuckistan and S4 clusters in kilometers are hard to find for reasonable prices...