you can't use kernel module build for 2.6.32 with kernel 2.6.38 - no love
you can't use kernel module build with gcc 3.4 (driver for kernel 2.6.32) with kernel build with gcc 4.4 (kernel 2.6.38) - no love
uninstall everything that you installed "debian way", uninstall all xorg package for other cards - leave nouveau and vesa only.
Delete xorg.conf - should be no xorg.conf at all. Clean grub from changes.
Reboot with nouveau.
Download nVidia driver from nVidia (*.run package).
Edit /etc/default/grub to have line
make "sudo update-grub
Make sure that /etc/modprobe.d/fbdev-blacklist have no "blacklist vesafb
" or "blacklist fbcon
Make sure that you use gcc 4.4 (cc -v)
Reboot to recovery, install driver by "sh NVIDIA-Linux-x86_64-275.09.run
" - make sure to make xorg.conf with nvidia-xconfig during that and install 32bit compatibility part.
Reboot to normal kernel.
PS: I'm currently running 275.09 with Linux Mint Debian Edition with kernel 2.6.38-2-amd64 with no problem at Lenovo T61p laptop.