Its the wrong textures.

[NitroPower]

Ive installed a clean copy, no addons, into my desktop several times, and every time i play it, the textures are in the wrong place. For example: sometimes i see water as a land tile, or the texture for an airplane is confused with, say runway textures. And, the trees have building textures, while buildings have tree textures!

heres some of my system info:
------------------
System Information
------------------
Time of this report: 5/9/2008, 21:54:50
     Machine name: COATES09132006
 Operating System: Windows XP Professional (5.1, Build 2600) Service Pack 2 (2600.xpsp_sp2_qfe.070227-2300)
         Language: English (Regional Setting: English)
System Manufacturer: Gateway
     System Model: GT5082
             BIOS: )Phoenix - Award WorkstationBIOS v6.00PG
        Processor: AMD Athlon(tm) 64 X2 Dual Core Processor 3800+,  MMX,  3DNow (2 CPUs), ~2.0GHz
           Memory: 1918MB RAM
        Page File: 303MB used, 3506MB 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: NVIDIA GeForce 6100
   Manufacturer: NVIDIA
      Chip type: GeForce 6100
       DAC type: Integrated RAMDAC
     Device Key: Enum\PCI\VEN_10DE&DEV_0242&SUBSYS_0CA8105B&REV_A2
 Display Memory: 256.0 MB
   Current Mode: 1440 x 900 (32 bit) (60Hz)
        Monitor: Plug and Play Monitor
Monitor Max Res: 1600,1200
    Driver Name: nv4_disp.dll
 Driver Version: 6.14.0010.8133 (English)
    DDI Version: 9 (or higher)
Driver Attributes: Final Retail
Driver Date/Size: 9/18/2005 11:32:00, 3905408 bytes
    WHQL Logo'd: Yes
WHQL Date Stamp: n/a
            VDD: n/a
       Mini VDD: nv4_mini.sys
  Mini VDD Date: 9/18/2005 11:32:00, 3493984 bytes
Device Identifier: {D7B71E3E-4102-11CF-2E6C-A22C03C2CB35}
      Vendor ID: 0x10DE
      Device ID: 0x0242
      SubSys ID: 0x0CA8105B
    Revision ID: 0x00A2
    Revision ID: 0x00A2
    Video Accel: ModeMPEG2_A ModeMPEG2_B ModeMPEG2_C ModeMPEG2_D ModeWMV9_B ModeWMV9_A
Deinterlace Caps: {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(YUY2,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_BOBVerticalStretch
                 {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(UYVY,UYVY) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_BOBVerticalStretch
                 {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(YV12,0x32315659) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_BOBVerticalStretch
                 {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(NV12,0x3231564e) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_BOBVerticalStretch
       Registry: OK
   DDraw Status: Enabled
     D3D Status: Enabled
     AGP Status: Enabled
DDraw Test Result: Not run
D3D7 Test Result: Not run
D3D8 Test Result: Not run
D3D9 Test Result: Not run

[Daube]

Err... So it looks like your textures are completely messed-up, right ?
The 6100 video card is quite low end... either you're getting video memory problems, either overheating hardware...
A good start may be to run a full error-check on your hard drive.