I've now got BIAB 2012 with the BIAB2Go export feature for my iPad running correctly on my laptop.

I had to go through a methodical removal of everything related to BIAB first, and I then reinstalled everything with the program files on the (relatively small) C drive and RealTracks and Drums on the (spacious) F drive.

I think my problems arose because I had installed BIAB on the laptop when it only had the C drive, but had to add an external drive when I bought a few more RealTracks. I installed another version of BIAB on the F drive, so that I could run this when the F drive was attached, but run on a restricted set of RealTracks on drive C only for portability.

There are one or two features of BIAB<=>iPad communication which don't quite work the way I expect, but I'll play with this some more before posting any conclusions.