I also have the shutdown issue on mine.
When I close nwserver.exe with nwnx running, nwserver crashes, and then DW20.exe starts running getting a crash dump, which then blocks nwnx from starting a clean nwserver.exe process.
This often causes problems for my server reboots.
But addicted2rpg was working on a reboot of the odbc and chat plugins, and did find an inherent incompatibility with server 2008+
If any of the bugs the OP is seeing result in errors in faulting module ntdll.dll - then I'd say they are related.
Server 2003 is a good compromise for me - its close to the same level as Windows XP update wise, but still provides server level control.
Hosting mine in the cloud via amazon helps to a degree, but only if your willing to pay: (I host mine on a medium size server,$60 per month, but I utilize it fully with development projects on the side too (TFS and websites hosted on it))