You installed the Win8 Server Beta without issue, but you are unable to install any roles or features like Hyper-V role. It just fails, no events in the Event Log.
You can install Hyper-V role through powershell (e.g. Dism /online /enable-feature /featurename:Microsoft-Hyper-V), but you can not start any VM you created.
This is a known issue with the beta. Specifically - the user locale and the system locale need to match (they should not need to be English - just the same).
You can also change it in the Control Panel and Region. (Some customers reported the Format must be English (United States)).