Just tried upgraded from a 1.5.3 to 2.0.6 and the installation failed. I had been using a UNC path (\\MyServerName\Repositories) and that caused the service to fail to start at the end of the installation. I canceled, rolled back, and eventually installed with C:\Repositories just to get the thing installed. After some investigation, I had to manually edit httpd.conf because it had invalid paths in it.
Best, Kent
