Xionix Registry Serve

I purchased a license for Xionix regserve for three computers. It worked fine on the first machine, but, after installing it on the second, I got an error message I do not understand, and something that said the system could go around the problem if I clicked on "continue", which I did, but nothing happened. I have attempted to contact Xionix, which promises an answer within 48 hours (I first contacted them at least ten days ago), but they have not replied. Does anyone have a working telephone number for them or any advice as to how I can get an answer to this problem?

 

Thank you, plodr--I'll check out your suggestions!