Answer:
Up to RFEM 5.07.11, there was a problem with multi-core processors, such as Intel XEON.
Please try the two files attached to this FAQ on the problem computer.
Folder Program Files/Dlubal/RFEM 5.07 or Program Files/Dlubal/RFEM 5.07
http://download.dlubal.com/?file=Nexx.zip