Fix what items we are trying to get, make sure we're not trying to get things we can't spawn.

Glitterworld Prime/Utilities.cs

@@ -416,13 +416,17 @@ namespace Glitterworld_Prime
 
             // Then scan for Defs that can be traded.
             foreach (var thing in things)
+
                 try
                 {
-                    if (thing.tradeability == Tradeability.None) continue;
-                    if (thing.category == ThingCategory.Item && thing.thingClass.Name != "MinifiedThing")
+                    if  (thing.tradeability != Tradeability.None && thing.GetStatValueAbstract(StatDefOf.MarketValue) > 0.0 &&
+                        (thing.category == ThingCategory.Item || thing.category == ThingCategory.Building) &&
+                        (thing.category != ThingCategory.Building || thing.Minifiable))
                         thingsToRequestFromMarket.AddRange(ComputeThingDef(thing, stuffCategories));
+
                     // Add support for Minifiable buildings
-                    else if (thing.category == ThingCategory.Building && thing.Minifiable)
+                    else if (thing.category == ThingCategory.Building && thing.Minifiable &&
+                             thing.tradeability != Tradeability.None)
                         thingsToRequestFromMarket.AddRange(ComputeThingDef(thing, stuffCategories));
                 }
                 catch (Exception ex)