Actually something similar happened to me, but....

The new 9.2 Kernel worked for me with the 9.1 dsmos.kext in the extensions folder
so i use 9.1 dsmos.kext and 9.2 mach_kernel and it went thru

if you want try reinstalling the Whole DVD again but, at the end when it wants to restart, Quickly open Terminal and Delete the NV* & Ge* with the rm -rf thing so when you're up and running Leo install the Video Installer again

but your problem is not then the Video Kexts is the Installation itself of the Leo 10.5.2