"System error" - what is this?

"A critical error has occured and the process must be termianted".

Why do I get this now? It's been working fine for hours. I just joined a game, and it keeps crashing, and I cannot even play in the game I'm in without the application freeezing again instantly.

I tried restarting the client, but that doesn't help.

EDIT:

Okay, I found the problem: Leftover .exe from another game - nothing in any way related to this game, so leave my RAM alone, please.

How very nice of the error message to take full priority of the screen - had I not have more than 1 monitor, I wouldn't even have been able to see what was actually happening in Task Manager and finally rejoining the game.

I got in, and we won, but still:

You are ineligible to earn loot due to leaving or AFK behaviors.

Gee, thanks - I would have been back ingame a lot sooner, if not for the error message behaviour...