removed the OpenSim.Region.ScriptEngine.DotNetEngine reference from OpenSim.Region.Environment, as it created a round reference problem. And it doesn't seem like it was needed

prebuild.xml

@@ -474,7 +474,6 @@
       <Reference name="OpenSim.Framework.Console"/>
       <Reference name="OpenSim.Region.Physics.Manager"/>
       <Reference name="OpenSim.Framework.Servers"/>
-      <Reference name="OpenSim.Region.ScriptEngine.DotNetEngine"/>
       <!-- For scripting in funny languages by default -->
       <Reference name="Microsoft.JScript"/>
       <Reference name="XMLRPC.dll"/>