Same exact problem here...
Windows 2000 box (older Dual-P3 1GHz CPU Motherboard), dedicated to running just BOINC and the DDNS app...
No problems with the hardware itself... (If there was, I'd think that BOINC would be throwing errors as well).
Windows XP isn't an option on this ancient hardware, so if the Hostway DDNS app is indeed no longer supported under Win2K, then I suppose going to some flavor of Linux (Ubuntu?) would be the only viable solution...