Keep getting "A fatal DirectX error has occurred.(10000000)"

Hi!

I've been playing the game since release with no problems, all of a sudden today I start getting a "A fatal DirectX error has occurred.(10000000)" and the game freezes and shuts down. It only happens when I enter an instance (guildheist/dungeons etc) which is making the game unplayable, does anyone have a solution for this?

My current PC setup:

Windows 8.1 Pro Preview 64-bit
Motherboard: MSI MS-7721
Processor AMD A8-6600K
Memory: 4096MB
Video Card: Geforce GTX 650 Ti
DirectX Version: DirectX 11

I get this whenever I try to launch the game. I can't play at all. :/