White weapons ...

Um, i have never seen this happened, your crossfire folder might be bugged. Have you recently changed a file in your cf folder? If so, and you dont know what it is, re install cf again so you can get your proper cf files.

Sounds like one of the following problems:

The game failed to load a rez file with the weapon textures in it.
The weapon texture rez files were changed, modified or deleted.
A game hack caused the weapon textures to change.
Could be possibly related to your video card.

Almost all of these kinds of cases can be solved by the following solutions:

Uninstall and reinstall CF.
Do not modify your rez files (note that some rez file modding can and will result in a suspension or ban)
Do not use a hack program.

For video card errors make sure to have the latest drivers installed for your card.