Installing WDM 4.8.5. Install on Windows Server 2008 Problems

Hi

I need to install the WDM Managenemt Software on a Windows Server 2008 (german) - 32 Bit machine.

When i start the installer without any options set - i'm getting the error :
"WDM does not support this version of the operating Syste, aborting installation"

If i change the Compatibility Settings to WIndows Server 2003 the installer will start but stop during setup with "Unable to configure Rapport user. Aborting Installation"

any hints on how i can get the software installed on my system ? Should i use a different version ? Did i forget to install any prerequisites for the Rapport user ? ??

Florian