Im not having a problem with this. I have vista 64 at home and use a XP machine and a vista business 32bit laptop at work. My 100gb drive i take between work and home daily i have no trouble with it not reading on any machine. Are you sure that the business machine is not using bitlocker?, ive had no experience with bitlocker yet but i cant think of any reason why that would happen other than bitlocker or maybe the vista machine was still writing to the hard disk when it was removed from the system (could but not always causes problems) did you stop the device before removing it?
Also if you ask me, they shouldnt banish your Vista test bed boxes because of this, these are the sort of problems you want to acknowledge and find a fix for in a test enviroment