Moved from:
http://forum.square-enix.com/ffxiv/threads/19174-Random-crashes-in-Gridania

Platform: Windows 7 64-bit
ISP: Qwest
Type of Internet Connection: Fiber
Internet Connection Speed: 40Mbit
Date & Time: 08/01/2011 10:00 AM Mountain
Frequency: Often
Character Name: Coors Light
Race: Lala
World: Lindblum
Class/Skill Rank: THM 49
Physical Level: 50
Area and Coordinates: Gridania 4,6
Party or Solo: Solo
NPC Name: N/A
Monster Name: N/A
In-Game Time: ~1:00
Steps:
1. Just running through Gridania often causes Nvidia Direct X error with nvlddmkm causing game to crash.

The error is Unable to detect DirectX device. The program has shut down. Happened again at 6,4 in Gridania.

Only happens in Gridania and nowhere else. Running nvidia GTS 360M graphics on Asus G60JX laptop with latest patches to Windows 7 Enterprise 64-bit and latest nvidia drivers for 360M card.