I compile my own kernel a lot of the time, so installing VMware tools always compiles its own modules against the source tree where the kernel was actually built. Today I built the VMware modules against the stock Debian kernel. This message had everything I needed to know:
Make sure you have the linux-headers package installed for you current linux-image. IOW, if you have linux-image-2.6.18-4-k7 as you current kernel, you will need linux-headers-2.6.18-4-k7 (which will pull in linux-headers-2.6.18-4 as it depends on it). Another helpful package is “kernel-package”. That package makes sure you have everything you need to build kernel modules.
aptitude install module-init-tools linux-headers-`uname -r` build-essential