NX Motion Cosimulation License Error

I'm trying to do a Co-Simulation with NX Motion. Simulating hosted in NX works fine, but if i'm trying to use Simulink as Host, i get an error message: "ERROR - Unable to initialize [....] NX License Error: [...]" I'm not sure if this is an issue in NX or Matlab, but both NX and Matlab/Simulink work fine alone. Is there maybe an environment Variable missing for the NX-license file, that's needed by Matlab? Again, this error accurs only if I cosimulate Simulink-hosted. A couple of days ago I had no problems at all. Is there someone facing similar problems and/or is there a fix?

'ver' plots:

MATLAB Version: 8.2.0.701 (R2013b) Operating System: Microsoft Windows 7 Version 6.1 (Build 7601: Service Pack 1) Java Version: Java 1.7.0_11-b21 with Oracle Corporation Java HotSpot™ 64-Bit Server VM mixed mode

MATLAB Version 8.2 (R2013b) Simulink Version 8.2 (R2013b)

I'm using NX Version 8.5.3.3