Well, not sure about the error but:
The log indicates you are using 1.0-533x module not 4496. I would suggest that you download and 533x and reload the 533x nvidia module in Mandrake.
Mandrake uses the /etc/X11/XF86Config-4 for the config file. I wonder if you didn't edit the XF86Config file and that the two are not the same. Check that they are either the same or sym-linked.
BTW, I've only had to reload an OS twice (in 9 years of Linux) - both times the hard drive crashed. You should almost never have to reload the OS in Linux - it's not like the greasy M$ stuff ;-)
Hope this may be of some assistance.