diff --git a/scripts/spells.lua b/scripts/spells.lua
index 8269e72e6..29991376c 100644
--- a/scripts/spells.lua
+++ b/scripts/spells.lua
@@ -1,9 +1,14 @@
 function creation_message(mage, type, number)
   local msg = message.create("item_create_spell")
-  msg:set_unit("mage", mage)
-  msg:set_int("number", number)
-  msg:set_resource("item", type)
-  return msg
+  local err = 0
+  err = err + msg:set_unit("mage", mage)
+  err = err + msg:set_int("number", number)
+  err = err + msg:set_resource("item", type)
+  if err ~= 0 then
+      return nil
+  else
+      return msg
+  end
 end
 
 local function create_item(mage, level, name, number)
diff --git a/src/bindings/bind_message.c b/src/bindings/bind_message.c
index ae27573d9..6ff30e98a 100644
--- a/src/bindings/bind_message.c
+++ b/src/bindings/bind_message.c
@@ -72,6 +72,7 @@ int msg_set_resource(lua_message * msg, const char *param, const char *resname)
 {
   if (msg->mtype) {
     int i = mtype_get_param(msg->mtype, param);
+    const resource_type * rtype;
     if (i == msg->mtype->nparameters) {
       return E_INVALID_PARAMETER_NAME;
     }
@@ -79,8 +80,12 @@ int msg_set_resource(lua_message * msg, const char *param, const char *resname)
       return E_INVALID_PARAMETER_TYPE;
     }
 
-    msg->args[i].v = (void *)rt_find(resname);
-
+    rtype = rt_find(resname);
+    if (rtype) {
+      msg->args[i].v = (void *)rtype;
+    } else {
+      return E_INVALID_PARAMETER_VALUE;
+    }
     return E_OK;
   }
   return E_INVALID_MESSAGE;