I 've downloaded CDRWIN5 too although their latest version
is 3.9C (goldenhawk.com)
Didn't find my way in the menus of cdrwin5 and googled around
but found little info.
Finally I tried to burn my redhat ISO using the icon on the left
'Write CD-Image' , dragged my ISO and 'Start' .
My CD was written and bootable and all.
I hope this helps a little.
www.cdrwin.info