diff --git a/BizHawk.Client.Common/lua/EmuLuaLibrary.UserData.cs b/BizHawk.Client.Common/lua/EmuLuaLibrary.UserData.cs
index 2cfa50814e..3e280ace40 100644
--- a/BizHawk.Client.Common/lua/EmuLuaLibrary.UserData.cs
+++ b/BizHawk.Client.Common/lua/EmuLuaLibrary.UserData.cs
@@ -21,6 +21,15 @@ namespace BizHawk.Client.EmuHawk
 		[LuaMethod("set", "adds or updates the data with the given key with the given value")]
 		public void Set(string name, object value)
 		{
+			if (value != null)
+			{
+				var t = value.GetType();
+				if (!t.IsPrimitive && t != typeof(string))
+				{
+					throw new InvalidOperationException("Invalid type for userdata");
+				}
+			}
+
 			Global.UserBag[name] = value;
 		}
 
diff --git a/BizHawk.Common/BizInvoke/BizInvoker.cs b/BizHawk.Common/BizInvoke/BizInvoker.cs
index c00ad96da4..8ebdf321a3 100644
--- a/BizHawk.Common/BizInvoke/BizInvoker.cs
+++ b/BizHawk.Common/BizInvoke/BizInvoker.cs
@@ -413,7 +413,7 @@ namespace BizHawk.Common.BizInvoke
 		{
 			if (type.IsGenericType)
 			{
-				throw new InvalidOperationException("Generic types not supported");
+				throw new NotImplementedException("Generic types not supported");
 			}
 
 			if (type.IsByRef)
@@ -421,7 +421,7 @@ namespace BizHawk.Common.BizInvoke
 				var et = type.GetElementType();
 				if (!et.IsPrimitive && !et.IsEnum)
 				{
-					throw new InvalidOperationException("Only refs of primitive or enum types are supported!");
+					throw new NotImplementedException("Only refs of primitive or enum types are supported!");
 				}
 
 				var loc = il.DeclareLocal(type, true);
@@ -437,18 +437,18 @@ namespace BizHawk.Common.BizInvoke
 				var et = type.GetElementType();
 				if (!et.IsValueType)
 				{
-					throw new InvalidOperationException("Only arrays of value types are supported!");
+					throw new NotImplementedException("Only arrays of value types are supported!");
 				}
 
 				// these two cases aren't too hard to add
 				if (type.GetArrayRank() > 1)
 				{
-					throw new InvalidOperationException("Multidimensional arrays are not supported!");
+					throw new NotImplementedException("Multidimensional arrays are not supported!");
 				}
 
 				if (type.Name.Contains('*'))
 				{
-					throw new InvalidOperationException("Only 0-based 1-dimensional arrays are supported!");
+					throw new NotImplementedException("Only 0-based 1-dimensional arrays are supported!");
 				}
 
 				var loc = il.DeclareLocal(type, true);
@@ -494,6 +494,11 @@ namespace BizHawk.Common.BizInvoke
 				return typeof(IntPtr);
 			}
 
+			if (type == typeof(string))
+			{
+				throw new NotImplementedException("Cannot marshal strings");
+			}
+
 			if (type.IsClass)
 			{
 				// non ref of class can just be passed as pointer
@@ -527,7 +532,7 @@ namespace BizHawk.Common.BizInvoke
 				return type;
 			}
 
-			throw new InvalidOperationException("Unrecognized parameter type!");
+			throw new NotImplementedException("Unrecognized parameter type!");
 		}
 	}
 
diff --git a/output/dll/nlua/NLua.dll b/output/dll/nlua/NLua.dll
index cf7b21bb1c..59fe2bc9d5 100644
Binary files a/output/dll/nlua/NLua.dll and b/output/dll/nlua/NLua.dll differ