Windows Vista Vista Update From XP: Loses ipconfig and nslookup commands

I recently had submitted a post stating that I had lost my ipconfig and nslookup functionality in the DOS window, and then later found that just by loggin out and re-logging in it fixed the problem (or at least I thought).

Well that problem has re-emerged and logging out and back in again is not helping. Has anyone else experienced this probelm?

BTW, I am running on an upgraded XP system which seems to work just fine apart from this problem.

Thanks!