KDM/X hangs on 64 bit debian

["Wackojacko" <wackojacko32@ntlworld.com>]

I just installed the 64 bit port of debian, via the sid net install, onto a 
new partition.  I am having problems with X and KDM.log gives me 'Null 
image' errors for QImage.  Googling suggests that this error means something 
else is using the monitor, and running the Nvidia Installer says that a 
current X session is running and exits.  I've tried kill -9 -1 without 
success.

The only thing I can think of that may be causing this is that I am using 
the same /home directory as my 32 bit debian sarge uses, could this be the 
problem?  If so how do I change the /home directory of the 64 bit 
installation?

TIA

Wackojacko