Are you sure the batteries are good / installed properly? See pg. 9 "Battery System" in the manual for more info. It sounds to me like the batteries were dead or installed incorrectly so when you unplugged it to take it to your business, the programming was lost. If this is the case, you'll have to reprogram the register, after remedying the battery problem, of course. If this was not the case, post again and I'll see if I can help.
Steve, December 2009