Kessler,
I had the same problem when I installed 7.1.
See: http://forums.ni.com/ni/board/message?board.id=170&message.id=86116#M86116
Never was able to get it solved...my local rep worked with NI Austin on the phone for hours...never got it solved, so I just went back to 7.0.
When I hear that they've fixed it, I'll install my upgrades (probably LV rev 8.0)
It's not a problem if your good at LV, but if you're a first-timer, just learning LV,it's a real pain!
Good luck,
Mike