Hi. I now have Backtrack 4 installed on my HD. I have the linux drivers. Tried to install them, but I need help.

I get errors like this after I used the tar command and cd'd to the directory of the drivers

i type in "make"

make: *** lib/modules/2.6.21.5/build: No such file or directory. Stop.
make: *** [modules] error 2

help?