--- mapnik-0.7.1/include/mapnik/factory.hpp~	2010-03-22 16:40:04.000000000 +0000
+++ mapnik-0.7.1/include/mapnik/factory.hpp	2012-04-05 15:55:13.460191219 +0000
@@ -84,7 +84,7 @@
             {
                 return (pos->second)(file);
             }
-            return on_unknown_type(key);
+            return this->on_unknown_type(key);
         }
     };
 }