Can't open DWG files, if DraftSight is active

Hi there )) I'v big problem.

OS: Linux Mint 17.1 cinnamon 64bit

Soft: DrafSight 15 free

Problem: If DraftSight is active, can't open file, from the file explorer "Nemo" (double click on *.DWG in Nemo).

Second file can open, just file>open...