Problems with ADMS 3 programming software?

Been using the ADMS 3 software to programme a Yaesu VR500 radio on a computer running wndows XP (service pack 2) without problems for a while now. Had to reinstall it recently on a different machine which appears to be running XP service pack 3 and am now having problems with the software. If I try to open any of my saved .rdf files I get a mesage reading "file settings do not match current settings for vr500, invalid frequencies will be deleted". Trying to type a frequency other than 1.0000, into the programme results in the error message "this is not a valid frequency". Trying to read data from the radio results in a "timeout" message and the memory is wiped on the radio too, the com ports are configured correctly too.  Is the software compatable with xp service pack 3 or is there another patch? will the software run on the new Windows 7 operating system?
I have the com port configured to port no 4. I have a programme which scans the com ports and it confirms that "an RT systems cable is connected to this port" without the software running, the software is  configured to use  port 4.  When the VR500 software is running and I do the port scan again, it confirms that a programme is using port 4. Port 4 also appears in the device manager when the cable is connected (and disappears when I unplug it). The problem I have is that I cannot get the data to the software from the radio. I get a timeout error on the software and the radio is wiped clean and reset.

I successfully set up and ran the software on someones  note book pc yesterday configuring it to run with port 4 and then port 2 and it worked fine. The only thing different was, that machine was running XP service pack 2 like my old one, this one is service pack 3 ? I have successfully used the programme on two different computers running service pack 2 this is a UK model by the way.