Crashing at start

StrikerX3

I am unable to run build 252. The game crashes immediately after starting. Here's the log.txt:

Date: 08/28/13
Time: 21:46:07:

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Build 252
Windows 7 64-bit (build 7601)
Error: PhysX: Invalid Cuda context!
Steam initialized
Num displays: 1
Direct3D 9 initialized: NVIDIA GeForce GTX 680 (9.18.13.1407)
Error: Couldn't load 'renderer/Drawer.shader' (file not found)


Things I already tried:
- Verifying the integrity of game cache on Steam (no errors)
- Reinstalling the game after deleting everything (same error)
- Removing the %APPDATA%\Natural Selection 2 folder (still same error)
- Video and motherboard drivers are already up-to-date
- The file mentioned above is at C:\Program Files (x86)\Steam\steamapps\common\Natural Selection 2\core\renderer\Drawer.shader (the default Steam installation folder) and looks fine
- Also tried changing permissions to Full Control on every file within the Steam NS2 folder to my Windows user account, still no go
- Tried D3D9, D3D11 and OpenGL in the system_options.xml file
- Disabled and enabled PhysX on GPU (driver and system_options.xml)
- Copied the Drawer.shader file to several places within the Steam NS2 folder
- Works fine on my notebook which is also Windows 7 64-bit, Core i7-2630QM, Geforce GT 540M
- Tried copying over both the Steam and the AppData folders from the notebook to the PC, still the same error

StrikerX3

Running as administrator seems to have worked, but that's not the kind of solution I'd like to use forever...