I have read about this problem so many times in this forum now and its always suggested and said that its your copy of winxp, so try too make a new copy and maybe that will help. There is also a file called crc.exe that you could run too check if your copy of winxp is good, but i do not know where that file is, do not think its on the winxp cd.
Hope it helps some.
Roltec