Disk Director 11 Adv. for server

Hello.
I am facing two problems.

First, our server is running a product called Acronis Disk Director 11 Advanced Agent.
I can't figure out why but we cannot uninstall it.
The reason there is unclear to us: when in "Control Panel \ Programs and Features" we select the voice of the software in question and then click on "uninstall", the uninstall process starts but then stops. We see the progress bar that grows first, then stops and then decreases. So that the software in question still remains there.
That product is installed on a Windows Small Business Server 2008 box.

Not only.
When we try to reinstall Disk Director 11 Advanced for Server launching the file-ADD11A_12077_en-us.exe, the installer tells us that on the machine is already installed a product in a different language.
Well, the only Acronis product that is listed in "Control Panel \ Programs and Features" is precisely Disk Director 11 Advanced Agent.

So, what can we do to uninstall Disk Director 11 Advanced Agent and to install Disk Director 11 Advanced for Server again?

Thank you for your attention, best regards.
Riccardo