I have NIS 2011, WinXP SP3. Have been using NIS for several years on multiple systems. I've never seen this problem .
I receive the following popup at some point , each time I start up.[" to receive the most current updates you must restart your system"]
Sometimes it is several minutes or more before it appears. The main screen says "secure", green check . I can manually run liveupdate. It appears to work, ie., searches for updates, downloads, and installs, and doesn't ask for a restart. I don't see evidence of this being a "common" problem. I will probably have to R&R NIS to solve it. The only thing out of the ordinary that has happened was a problem with my ISP, where I thought I had a problem, and wound up doing a system restore to the day before. The problem turned out to be the connection. I'm guessing that something didn't go well with the restore, even though everything else seems to be fine.