Texture problems

[Special K]

Hey guys,
I have some problems with textures. In any textures which have "gaps" in them (like the gaps between the tank trap spikes or gaps within trees), they're filled black. It's nothing major, but if there is an easy solution for this, I'd be grateful.

On another note, is it normal that spike traps when placed on slopes float in the air?

Here are examples:

[Staff]

That is a video driver problem.
It isn't showing alpha correctly.

[Special K]

Ok, and how can I fix this problem? My graphic drivers are fully updated.