Upgrade from SUSE 12.5 to 15 failing

I'm trying to upgrade a VM server from sles 12 SP5 to 15 through a boot from a virtual CD ( [SLE-15-SP5-Full-x86_64-GM-Media1.iso] But im getting this error after boot, and initial load:
Error
Internal error: private constant Y2Package ProductUpgrade MAPPING refrenced.

I get past the welcome screen, the problem occurs right after i click "next" in the mounting partitions screen

Any pointers would be appriciated