@synchromesh
Because I have had the occasional same error message on test levels that I have had to abandon because of the same message.
Would you please explain what you did to correct the issue.
I have found what I believe is the cause in my case but no solution.
This happens when I use the F9/E function in a test level to move around entities with out changing from Pre-bake to Realtime first.
Sometimes something goes wrong in the pre-bake level with out any indication of a problem until I return to the editor, save the level and then try to run the test level with the changes made using F9/E.
If I save the level after returning to the editor then the level will no longer run because of the indicated error message.
Windows pro 8.1 with 8.1 update,64 bit|AMD FX-6200 Six-core-3.80 Ghz |CPU PASSMARK 6,142 |Memory 10GB |NVIDIA GEFORCE GTX 660 SC |GPU PASSMARK 4,114