Thanks.
I have three keys in total. One is the master key (small, black, plastic key), one is a simple key without remote functions and the third one is the one with full remote functions. The third one stopped at some point operating the remote functions (lock/unlock) but did start the engine. I went through the programming sequence I found on the site and all the remote operations were restored....however, the key stopped starting the engine. The simple spare key didn't work either!!! My only salvation was the master key! And I say salvation, because I reside in East Africa and the BMW dealer here is the lamest ever.
Anyway, the fact that the spare key became inactive as well, makes me think that the mobilizer code changed altogether. Question is...can this be a DIY thing, or do I have to refer to the dealer?!