We had same issue with a user running win7 x64 and nx8.0. I foound out it worked with another user that never was logged on before so it had to be something with local user setting checked registry for user but it was not the problem. it was in the stored local user profile c:\users\%userprofile%\appdata\local\Unigraphics Solutions\nx8
By Deleting the NX8 entry it will at next start of NX8 create a new directory and it will all work. A tip could be to always make a copy of entry before delete anything.