There are several known causes of this issue:

1. Your -game path is incorrect. Your -game path needs to point to the gesource folder. If the path has spaces, ensure it is wrapped in “double quotes”.
   
   
2. Windows: You may be missing the 32-bit Microsoft Visual C++ 2012 redistributable, or mistakingly installed the 64-bit version instead.
   
   
3. Linux: If you're using a WINE-based server, you may have defined the DISPLAY variable but aren't actually running an X server. If you're running a headless server, make sure Xvfb is running and that DISPLAY is pointing to the correct display.