Ther is an error when loading my game. this is what it says:

'materials_dx7/techniquesets/filter_symmetric_4.techset'
WARNING: Could not find material 'filter_symmetric_4'
ERROR: Couldn't open techniqueSet 'materials_dx7/techniquesets/filter_symmetric_5.techset'
WARNING: Could not find material 'filter_symmetric_5'
ERROR: Couldn't open techniqueSet 'materials_dx7/techniquesets/filter_symmetric_6.techset'
WARNING: Could not find material 'filter_symmetric_6'
ERROR: Couldn't open techniqueSet 'materials_dx7/techniquesets/filter_symmetric_7.techset'
WARNING: Could not find material 'filter_symmetric_7'
ERROR: Couldn't open techniqueSet 'materials_dx7/techniquesets/filter_symmetric_8.techset'
WARNING: Could not find material 'filter_symmetric_8'

------- sound system initialization -------
Attempting 44 kHz 16 bit stereo sound
couldn't initialize 2D provider: waveOutOpen() failed.
Error during initialization:
EXE_ERR_MSS_INIT_FAILED_MP

What does this mean? how do I fix it?

Make sure you have a legit copy of the game first.
If you do then try reinstalling DirectX 9, your sound card drivers and call of duty 2. That might fix the problem

It looks like COD2 could not properly load files for DirectX and it had trouble with your sound at 44kHz. So after you reinstall your game, leave the options at what the game gives you (don't raise them) and try leaving your sound below 44kHz (try 22 kHz)

quote monkey_ninjas316

Make sure you have a legit copy of the game first.

Yeah, you know, just incase you forgot you didn't actually spend the 50 bucks on this awesome game.