Seems many people hare having problems with this.
Try apt-get and install kernel-headers-2.6.0-1-386 or something like that.
then add --kernel-include-path /usr/src/kenrel-headeres-2.6.0-1-386/include when you execute the innstalation script.
Dunno if the official drivers are working with 2.6 yet tho. Try looking for a modified driver at minion.de if you still have porblems after the innstalation.
Gentoo GNU/Linux - 2.6.10-rc2 - Shuttle SN45G - AMD XP-M 2400+ @ 2.4ghz - 1024 MB RAM - GeForce 4 TI4800SE - Nvidia driver V.1.0.6629