Why can't I get the Continuous burst mode in a Nikon d7000 to work?

So, I recently got the Nikon d7000 and would like to use the burst mode. I clicked on the release mode dial lock and turned the release mode dial to CH. This burst mode should give me 6 fps, but instead I get about 1fps when I hold down the shutter for several seconds.

I've tried different modes to get 6fps (scene modes, auto, P mode with high shutter speeds, S mode with the highest shutter speed, various A & M modes) and whenever I press the shutter I get these really slow clicks (about 1 fps).

I would like to point out that I was able to do this at one point, but now I can't. I'm not sure if I touched something when I first got it, but does anyone know why this is happening? How would I be able to fix it?

One thing that could slow continuous shooting is shooting RAW, because the large files can fill the buffer. However the first few shots should be fast.
Another possibility is if you have Active D-Lighting turned on. The processor needs time to run that for every shot.

Modes have nothing to do with it. Do some homework in the owner's manual - details are there.