I installed these pups in my strat and i followed everything the schematic said, except for one part. And the consequences are crackles, buzzing sounds, etc. I did the grounding right, the on to the output jack, and the one to the "spring claw" (guessing it was the normal metal plate where the springs clip to), but there was another that says "ground to body cavity" and it is a picture of a wire with some weird oval shape looks like this:

I have no idea where that goes, and if that is my problem. Help?
Oh, sorry. The body cavity one comes off the volume. Then the 2 wires off the volume pot to output jack, then the spring claw that comes off the volume pot. So no, no grounds from the tones.
Is the cap going straight to ground, then?
I wire my tone controls differently, so i have the tone cap going in between the volume and tone control...then a wire comes off the tone and goes to ground.
But a lot of people these days just have the cap go to ground.

Another potential problem might be cold solder joints. Are all your blobs of solder shiny? If not, you'll have to do it again.

I don't know what schematic you're using...
Any chance I could see it?

Better yet, pics of the wiring?
Yeah, I have to head out right now, but ill PM you when I get back with the pics, because I have to take the PG off, and the holes are pretty stripped already, but I need to take it off to check everything. What do you mean shiny? what happens if they aren't?
I've never had a problem with making solder joints - haven't gotten any cold ones - at least, inside my guitar's electronics.
One guy came in here and had some, and he was having problems with his output. It's a less reliable joint, conductivity is poor.
You can avoid cold solder joint by not distrubing a newly soldered joint for maybe 20 seconds after soldering it. Moving it or whatever can screw a good one up.
As for the stripped holes, you could use a toothpick and rub a little bit of wood glue on the inside of the hole, if it's really becoming an issue.