When installing QVS 64, stops at 'register QVB error'. What to do?

[#1]

Dear experts,

When installing QVS 64, stops at 'register QVB error', and the installing roll back. What to do to keep installing QVS?

Is anyone can help this?

We look forward to hearing from you, many thanks!

[#2]

More details re above situation: uninstalled QVS 9 from Windows 2008 and tried to re-install QVs 9 on Windows 2008. The installation rolled back.

[#3]

Have you switched off the UAC (User Access Control)?

It is often neccessary to do so during installation. After you are finished you can switch it on again.