This is 100% a UAC problem. I have seen this before, even when logged in as my account which was a domain admin account.
Do the following:
1. Disable all of UAC (temporarily) (requires reboot)
2. log in as LOCAL admin, not a domain account but the local admin account on the server itself.
Right click on VmwareConverter and 'run as administrator'
I will be you will then see all your HDs listed 