Unfortunately 64-bit version requires rewriting the app completely from scratch (yeah, we are that old).
Please inspect program logs for error messages. Also you can try to inspect Windows event log.
MarketFeeder is really complex software due to ability to "run client's code" (triggers) where could be unlimited variants of trigger expressions causing the crash (and haven't covered by our tests).
Mind sending your triggers and settings file to our support to run tests on our side.
Thank you.