I believe he's saying that he's unlocked the case and some (Or all) of the functions, but no Mechjeb bar is appearing on the side of the screen regardless. I can confirm this, as it is happening to me as well, though I'm going to hazard a guess and say it's due to running the 64-bit version. I haven't bothered to fire up 32-bit since x64 came out. Mostly because I'd rather have my game not crash after every attempt to recover a vehicle than have working Mechjeb.