Bootable installation cd problem

Hello

I am trying to install suse linux 7.3 on my ultra sparc 5 workstation. 
I downloaded the CD ISO images from ftp.suse.com and burned them
successfully (on windows platform with ahead nero burning software).

The problem is; i cannot install suse with these CD's, as my workstation
does not boot with the first installation CD. 

I think the problem is the block size. When burning the ISO images, the
nero software uses 2K block size(with no option). 
I don't know how i can create CD rom installation disks with 512 bytes
block. 

Please help.
Thank you in advance.

Burak AYDIN.