Just in case it happens again, this is what FaHWiki says for that error: Corestatus 63(99).This is it chris I haven't had any issues since, and since I overclocked to 3.4GHz I have increased my PPD to 2200 approx.
Glad it's working for you, those quads scale nicely with an OC. If you are lucky enough to get the 2653 (1760pt) WU it will do over 3100ppd...
With the SMP for Windows client, a CoreStatus = 63 can either be a permissions problem or a MPI registration problem, or both. To fix the problem, set the properties of the fah.exe file to "Run as Administrator" and then run the "install.bat" file again to register MPI and the SMPD service.
Failure to install .NET 2.0 (Win 2K, XP) prior to installing the SMP client can also result in this error.