Are your machines with UEFI firmware? If so - bad luck as they are not supported (p.19 in the guide). The reason is not the firmware itself (Converter supports UEFI) but the boot loader. SLES use GRUB with BIOS machines but ELILO with UEFI machines and Converter doesn't support ELILO.
If this is not the case, please attach the full log bundle. GUI logs are not useful.
Regards,
Plamen