Try to turn off the texture preload options in your video settings if you have them enabled.
My offline practice/missions crash every time to the "encountered error must close down" error.
I don't have the pre-load turned on but I had texture size set to 512. I thought perhaps the offline stuff needed to be set at 1024, so I changed it... no soap
I guess I'll need to wait till there's a patch.
System Information
------------------
Time of this report: 4/20/2008, 12:45:42
Machine name: THE_BEAST
Operating System: Windows XP Home Edition (5.1, Build 2600) Service Pack 2 (2600.xpsp_sp2_gdr.070227-2254)
Language: English (Regional Setting: English)
System Manufacturer: Compaq Presario 061
System Model: EX321AA-ABA SR1930NX NA630
BIOS: Phoenix - AwardBIOS v6.00PG
Processor: Intel(R) Pentium(R) 4 CPU 3.06GHz (2 CPUs)
Memory: 1022MB RAM
Page File: 557MB used, 1804MB available
Windows Dir: C:\WINDOWS
DirectX Version: DirectX 9.0c (4.09.0000.0904)
DX Setup Parameters: Not found
DxDiag Version: 5.03.2600.2180 32bit Unicode
Display Devices
---------------
Card name: Radeon X1600/X1650 Series
Manufacturer: ATI Technologies Inc.
Chip type: ATI Radeon Graphics Processor (0x71C2)
DAC type: Internal DAC(400MHz)
Device Key: Enum\PCI\VEN_1002&DEV_71C2&SUBSYS_23421002&REV_00
Display Memory: 512.0 MB
Current Mode: 1280 x 960 (32 bit) (60Hz)
Monitor: Plug and Play Monitor
Monitor Max Res: 1600,1200
Driver Name: ati2dvag.dll
Driver Version: 6.14.0010.6734 (English)
DDI Version: 9 (or higher)
Driver Attributes: Final Retail
Driver Date/Size: 11/1/2007 20:09:00, 268288 bytes