Sounds like you have been doing some good trouble shooting. Is the Juke Box problem only with songs that have RealTracks or does it crash with midi files as well? Also, did you confirm that all of these songs will play fine one at a time in BIAB? Regarding memory and hardware, what amount of ram and free hard drive space do you have available on these two machines? Which OS?
I hope you can figure out the cause of your problem. I suppose it could be the Juke Box but it sounds like (from other post) that most folks don't have these issues.
Good luck and keep trying.