I have the same problem. I beleive it occurs because this update was assigned a version number that is lower than the previous version. Therefore, the system rejects it. Check the version number of the file outlfltr.dat installed in your system. The previous version is 1.4.5107.1103 dated 2/8/07. The number for KB931764 is 1.4.5106.1368 dated 3/6/07. I beleive that the issue will automatically go away when they issue the next version. In the mean time, I turned automatic update off. I'll check for the updates manually.
