[expert] live_update problem

[Expert User]

I am running Mandrake 7.2, with custom kernel 2.2.17.
I am trying to upgrade to Mandrake 8.0.
I have downloaded all the 8.0 directory(I have DSL!) in /usr/tmp/mdk8 
directory.
As root I cd to /usr/tmp/mdk8 directory and run ./live_update. it pops 
up a window saying press upgrade to 'Upgrade' after I press Upgrade 
button, it starts doing something and then just crashes. What is wrong? 
Can't I run live_update from hard disk? do I HAVE TO burn a CD, and then 
run live_update?

Please help