Go to Control Panel -> Administrative Tools -> Internet Information Services

Next, select Local comupter "Web Site" -> "Default Web Site" -> "ReleaseManager"

Then under the "directory security" tab click the "Edit" under "anonymous access and authentication control".

Uncheck the checkbox "Allow IIS to control password."

Then put the IUSR_<MachineName> into the Administrators group as a test.

Run IISReset. If you can now run the Release Manager application then either your IUSR_<MachineName> password was incorrect or that account doesn't have enough rights.