I recieved the same error and wrote to support and here is their response:
Thank you for your letter!
We know about this bug. More over it is bug of Windows XP.
Soon new version of Active Ports will appear and it will work under Windows
XP without any problems.
I let you know about it.
With best regards,
I posted this in the comments but since there is a thread I thought I'd post it here also.
Quite interesting since some people seem to have it running on XP.
I think it has to do with a service I have disabled. Don't think it is a network service as some with a network can't get it to work, but some can. I specifically asked that, but only got the reply posted above.