Two new updates allow Windows Essential Business Server 2008 (EBS 2008) to be installed into domains with existing Windows Server 2008 R2 Domain Controllers (DCs). “KB977193 How to install Management Server of EBS 2008 in a domain in which one or more domain controllers are running R2,” and “KB977195 How to run Preparation Wizard of EBS2008 in a domain in which one or more domain controllers are running R2.” To apply KB 977195 on machine you’re running Preparation Wizard on, simply leave default setting of “Install all available updates (recommended)” checked and select update button to continue. For KB 977193, Management Server’ll automatically download hotfix during installation if it has Internet connectivity. Use following steps to manually install update: Press SHIFT and F10 together to launch a command prompt, Using command prompt, navigate to where you stored update, Type following command: msiexec /update EBS2008-KB977193-x64-ENU.msp. Follow prompts to complete update’s installation. Reboot if prompted. Setup will proceed on restart.
More info: EBS blog