Update errors listing

svn path=/trunk/mcs/; revision=481

mcs/errors/errors.txt

@@ -8,4 +8,8 @@ numbers to match the Microsoft numbers:
 	of handling it.
 
 -2	Internal error, an interface is being defined inside an
-	interface (This should never happen).
+	interface (This should never happen).
+
+-3      Constant type is not one of sbyte, byte, short, ushort, int,
+	uint, long, ulong, char, float, double, decimal, bool, string, enum
+	or null type.