Error when upgrading from 1.7.3 to 2.0.2

[Alex]

I am receiving the following error when running the 2.0.2 MSI on our
1.7.3 server:

Custom action ConfigureSecurityExecute failed: Cannot
get effective rights from ACL: Access is denied.
(0x80070005)

I get the same error if I log in as Administrator.

Any ideas?

Thanks,  Alex.