add graceful handling of bogus actor types in import

OpenRA.Editor/LegacyMapImporter.cs

@@ -365,6 +365,10 @@ namespace OpenRA.Editor
 				//Structures: num=owner,type,health,location,turret-facing,trigger
 				//Units: num=owner,type,health,location,facing,action,trigger
 				//Infantry: num=owner,type,health,location,subcell,action,facing,trigger
+
+				try
+				{
+
 					var parts = s.Value.Split(',');
 					var loc = int.Parse(parts[3]);
 					if (parts[0] == "")
@@ -411,8 +415,15 @@ namespace OpenRA.Editor
 					if (section == "INFANTRY")
 						actor.Add(new SubCellInit(int.Parse(parts[4])));
 
+					if (!Rules.Info.ContainsKey(parts[1].ToLowerInvariant()))
+						errorHandler("Ignoring unknown actor type: `{0}`".F(parts[1].ToLowerInvariant()));
+					else
 						Map.Actors.Value.Add("Actor" + ActorCount++, actor);
-					
+				}
+				catch (Exception)
+				{
+					errorHandler("Malformed actor definition: `{0}`".F(s));
+				}
 			}
 		}