diff --git a/src/kernel/xmlreader.c b/src/kernel/xmlreader.c
index 887d04337..6ead426d1 100644
--- a/src/kernel/xmlreader.c
+++ b/src/kernel/xmlreader.c
@@ -1271,12 +1271,16 @@ add_skills(equipment * eq, xmlNodeSetPtr nsetSkills)
       propValue = xmlGetProp(node, BAD_CAST "name");
       assert(propValue!=NULL);
       sk = sk_find((const char*)propValue);
-      assert(sk!=NOSKILL);
-      xmlFree(propValue);
-      propValue = xmlGetProp(node, BAD_CAST "level");
-      if (propValue!=NULL) {
-        equipment_setskill(eq, sk, (const char*)propValue);
+      if (sk==NOSKILL) {
+        log_error(("unknown skill '%s' in equipment-set %s\n", (const char*)propValue, eq->name));
         xmlFree(propValue);
+      } else {
+        xmlFree(propValue);
+        propValue = xmlGetProp(node, BAD_CAST "level");
+        if (propValue!=NULL) {
+          equipment_setskill(eq, sk, (const char*)propValue);
+          xmlFree(propValue);
+        }
       }
     }
   }