Filters not available?

Using: Photoshop CS2

As seen in the following picture, I have two layers. One, a white rectange, and two, a black background. I want to use the wind filter on the rectangle, but the filter, for some reason, is not available in the filters menu.
I do have this filter. I have used it before. I have also tried merging the two layers, and then using the filter, but that doesn't work either.
I never used to have this problem with Photoshop 7. I have been coming across this problem frequently with photoshop CS2 though.
What the deal? Why are half the filters disabled sometimes? It is so annoying...

Some of the filters are only available to images in RGB mode. The wind filter, however, is available to both RGB and CMYK. The only other thing I can think of to check is whether you've accidentally changed your image to 16 bits per channel, in which case the filter will not be available. To check, go to Image>Mode and see if there's a tick next to 16 Bits/Channel. If so, tick 8 Bits/ channel instead. If this doesn't solve your problem, I'm stuck!

Thanks mate. I had it in 16 bits/channel. It's all good now.

Thanks a million!