I have spent the last 48 hrs on the phone with vMWare support about this issue. I had similar problems with installing SSO. It kept rolling back every time and vMWare support spent hours on the phone with me trying everything to solve this issue. They even tried to refer me to Microsoft Support and stated that it was an MSI install issue. Anyways, I was able to resolve the problem by clearing the CIS folder. DO NOT DELETE THAT FOLDER. We did that several times and it didn't work. You must leave the CIS folder, but delete the contents in there. Run the python perquisite install and re-run SSO install again.
Thanks again.