Check downloaded file MD5 checksum.
I have checked the MD5 checksum and it was correct. I even downloaded it a second time and I still run into the same problem. My initial suspicions are that the previous Beta did not get uninstalled either correctly or completely, which could be why the MSI fails.
Is there anyway of getting the Beta release that came out previous to the RC1? I know it's expired but I would like to see if that install works.