Can't Uninstall ABR Agent After Failed Upgrade

Hi,

We are using Windows 2008 R2 64bit.

I tried to upgrade our existing installation of ABR with the latest version 11639, but it failed at the Acronis Agent. Now I can't uninstall the Acronis Agent at all, no matter what I do. I extracted the AcronisAgentWindows.msi and tried Repair, Uninstall and Modify and it all ends with the message:

The installation was interrupted before Acronis Backup & Recovery could be installed. You need to restart the installer and try again.

This happens no matter which option I select - Repair, Modify, Uninstall

I've even tried to remove the software manually by following the instructions here:

http://kb.acronis.com/sites/default/files/content/2009/07/2975/win_2008…

The Agent is always listed in the Programs and Features list. I am now trying to go back to our original version and it fails because there is a newer version of the ABR Agent installed.

How can I remove this version so I can go back to the version that works? This is urgent as I am now without backup on my server, so any guidance ASAP would be most appreciated.

Thanks

Duke