I had the same problem as the first poster.
My solution was as follows:
1. uninstalled the Nvidia driver (5336) as follows: invidia-installer --uninstall (as root)
2. uninstalled the existing kernel source in DrakConf (changed video driver back to 'nv' so that I could boot into X)
3. Note: my kernel source was of a newer version that my existing kernel (2.6.3-9 vs 2.6.3-4), so I installed the kernel-source for 2.6.3-4
4. Re-installed the Nvidia driver, changed my X config file, et voila.
Surprised that I never had to reboot!