Index: pyyaml/trunk/lib/yaml/resolver.py
===================================================================
--- pyyaml/trunk/lib/yaml/resolver.py	(revision 222)
+++ pyyaml/trunk/lib/yaml/resolver.py	(revision 223)
@@ -75,4 +75,6 @@
 
     def descend_resolver(self, current_node, current_index):
+        if not self.yaml_path_resolvers:
+            return
         exact_paths = {}
         prefix_paths = []
@@ -96,4 +98,6 @@
 
     def ascend_resolver(self):
+        if not self.yaml_path_resolvers:
+            return
         self.resolver_exact_paths.pop()
         self.resolver_prefix_paths.pop()
@@ -132,9 +136,10 @@
                     return tag
             implicit = implicit[1]
-        exact_paths = self.resolver_exact_paths[-1]
-        if kind in exact_paths:
-            return exact_paths[kind]
-        if None in exact_paths:
-            return exact_paths[None]
+        if self.yaml_path_resolvers:
+            exact_paths = self.resolver_exact_paths[-1]
+            if kind in exact_paths:
+                return exact_paths[kind]
+            if None in exact_paths:
+                return exact_paths[None]
         if kind is ScalarNode:
             return self.DEFAULT_SCALAR_TAG