Mine kicked this up tonight whilst shifting from 2nd to 3rd (1500 miles 4 months old). Was literally in the middle of nowhere, car switched from S to M and locked me into 2nd (couldn't manually shift up or down, neither would it auto-shift).
Limped to a lay-by and turned the ignition off and on, message gone, car seems ok.
Obviously I'll take it to Audi asap, but anyone got and insight? There was an almighty clunk when the error came up (and I was under some pretty hard acceleration).