Right. I suspect that BK6 is true Windows compatible and therefore runs just fine on 64-bit while BK5 was Win-3.1 (which itself was based on DOS)-compatible and would not run on 64-bit.
I also run MYM (Managing Your Money) a DOS program and am glad that my laptop has Win 7 32-bit, and plan to stick with BK5.2G at least for the foreseeable future.
My other computers are XP and Vista 32-bit.
Bernie