Just a tip if you want to use 64 bit with BIAB..

Use something like LoopMidi (free) which creates as many virtual midi ports you like, and then run a host, Like Forte (latest version is 64 bit) or Cantabile (my preference - 32 or 64) to load a "rack" of VSTi's..

Set the tracks in BIAB to use the virtual midi ports and off you go...

You can also use VSTHost http://www.hermannseib.com/english/vsthost.htm a no frills free VST host....

Dennis