You're trying to use an 800MHz only radio on 700MHz? Seems that is the most relevant issue. Good luck with that....
(disregard if you mean some other "Baldwin County system")
As far as your immediate problem goes, if the same combination worked for the previous owner, then it would seem there may be a COM port or OS issue with your setup. As alluded too above that era of CPS was written to work with WIN XP. Using a more modern OS, or a drastically more modern computer, with pretty much any Motorola software than it was written for is usually frustrating at best, and disastrous at worst.