FC3>FC4 Upgrade Install Doesn't Find Existing Installation

[Andy Schlei]

I am trying to upgrade FC3>FC4.  I have booted from the boot.iso CD (burned) 
and am installing from HTTP with the source loaded on another machine on my 
local network.

My problem is that the installer does not find any existing implementation 
of Fedora, so goes into the new install path rather than the upgrade path.  
I have successfully upgraded a FC3 machine using this same approach (the 
test machine, which is now the source for the HTTP install) and the same CD.

I have faiirly standard partitioning using LVM.