getting started

Hello-
   With the purchase of a new (used) U2.
I decided to make the jump from RH6.2
to  Aurora 1.0.
   I downloaded the ISO's and burned a
CD that looked ok,  but I get
"Bad Magic Number"  when I try to boot
from it.  I took the warnings about burn
speed and burned it at x2.
   Does anyone have experience burning
from a Mac running OS X ?  I assume I
made a stupid error, but I have no idea
what it was.
   Thanks
Brian Cook