OS10.3 on 500mhz iMac

[KEVIN Lock]

I have been trying to load OS10.3 on a 500mhz slot loader iMac 
without success.  The CDs are genuine (purchased) and get about half 
way into the first CD before it all stalls and I have to restart and 
eject the CD.

Currently on 10.2.8; plenty of Ram.
A previous attempt caused a kernel panic and a Kev panic.     Zapping 
the pram somehow got me out of that situation.

Any ideas on this prob?

TIA

Kev