CTD after leaving game window

Pretty simple. It appears as though an exit from the game back to the desktop via alt-tab leads to a crash for the game when I return.

Debug Message: Version v1.91 Twilight of the Arnor last updated on: Thu May 1 12:15:51 2008
Debug Message: Checking DX Version.
Debug Message: *********DXDiag info follows.*********
System Info
Time: 6/9/2008, 22:31:59
DirectX Version: DirectX 10
Machine Name: MATTOP
Operating System: Windows Vista™ Home Premium (6.0, Build 6001) Service Pack 1 (6001.longhorn_rtm.080118-1840)
Languages: English (Regional Setting: English)
System Manufacturer: -
System Model: N/A
BIOS: Ver 1.00PARTTBL
Processor: Intel(R) Core(TM)2 Duo CPU T7500 @ 2.20GHz (2 CPUs), ~2.2GHz
Physical Memory: 3070MB RAM
Page File: 1405MB used, 4937MB available
Windows Dir: C:\Windows


Display Info
Display device 1:
Device Name: \\.\DISPLAY1
Card Name: NVIDIA GeForce 8600M GT
Manufacturer: NVIDIA
Chip Type: GeForce 8600M GT
DAC Type: Integrated RAMDAC
Key Device: Enum\PCI\VEN_10DE&DEV_0407&SUBSYS_002514C0&REV_A1
Display Memory: 1774 MB
Current Display Mode: 1680 x 1050 (32 bit) (60Hz)
Monitor Name: Generic PnP Monitor
Monitor Max Resolution:
Driver Name: nvd3dum.dll,nvwgf2um.dll
Driver Version: 7.15.0011.7474
Driver Date: 3/24/2008 02:52:00
DirectX Acceleration Enabled: Yes



Sound info
Sound device 1:
Description: Speakers (Realtek High Definition Audio)
Default Sound Playback: Yes
Default Voice Playback: Yes
Hardware ID: HDAUDIO\FUNC_01&VEN_10EC&DEV_0268&SUBSYS_14C00025&REV_1000
Manufacturer ID: 1
Product ID: 100
Driver Name: RTKVHDA.sys
Provider: Realtek Semiconductor Corp.
Driver Version: 6.00.0001.5523
Driver Date: 12/5/2007 18:28:52
Type: WDM
Other Drivers:
Acceleration Level: 1
Cap Flags: 0
Min/Max Sample Rate: 0, 0



Debug Message: *********END dxdiag info.*********
Debug Message: Entering WinMain
Debug Message: ******* Starting Game Shell *******
Debug Message: Going Fullscreen
Debug Message: Preparing to change display settings.
Debug Message: Using hardware vertex processing
Debug Message: Using multilsample setting: D3DMULTISAMPLE_4_SAMPLES
Debug Message: Attempting to create D3DDevice at resolution 1680 x 1050, Windowed: 0, Multisample: 4
Debug Message: Game Resolution: 1680 x 1050
Debug Message: Running fullscreen.
Debug Message: HAL (hw vp): NVIDIA GeForce 8600M GT
Debug Message: D3DPRESENT_INTERVAL_DEFAULT
Debug Message: Refresh rate: 60
Debug Message: Bit Depth: 32 bit.
Debug Message: *********Checking D3DDevice Caps***********************
Debug Message: A full-color cursor is supported in hardware at high resolution modes.
Debug Message: RGB in format 6:6:6, Masks reported as ff0000:ff00:ff
Debug Message: Now Fullscreen
Debug Message: Shell initialization complete
Debug Message: GalCiv2 is activated.
Debug Message: ***** Initializing Game *****

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