diff --git a/src/calibre/library/custom_columns.py b/src/calibre/library/custom_columns.py
index 86b7d715ea..83e6b029cb 100644
--- a/src/calibre/library/custom_columns.py
+++ b/src/calibre/library/custom_columns.py
@@ -262,7 +262,7 @@ class CustomColumns(object):
                             'SELECT id FROM %s WHERE value=?'%table, (ex,), all=False)
                     if ex != x:
                         self.conn.execute(
-                                'UPDATE %s SET value=? WHERE id=?', (x, xid))
+                                'UPDATE %s SET value=? WHERE id=?'%table, (x, xid))
                 else:
                     xid = self.conn.execute(
                             'INSERT INTO %s(value) VALUES(?)'%table, (x,)).lastrowid
diff --git a/src/calibre/library/field_metadata.py b/src/calibre/library/field_metadata.py
index 6f1219ad03..5a175ab2aa 100644
--- a/src/calibre/library/field_metadata.py
+++ b/src/calibre/library/field_metadata.py
@@ -315,10 +315,19 @@ class FieldMetadata(dict):
         for key in self._tb_cats:
             yield key
 
+    def itervalues(self):
+        return self._tb_cats.itervalues()
+
+    def values(self):
+        return self._tb_cats.values()
+
     def iteritems(self):
         for key in self._tb_cats:
             yield (key, self._tb_cats[key])
 
+    def items(self):
+        return list(self.iteritems())
+
     def is_custom_field(self, key):
         return key.startswith(self.custom_field_prefix)
 
diff --git a/src/calibre/library/schema_upgrades.py b/src/calibre/library/schema_upgrades.py
index 8d4fd5eba3..6222a8950f 100644
--- a/src/calibre/library/schema_upgrades.py
+++ b/src/calibre/library/schema_upgrades.py
@@ -289,6 +289,10 @@ class SchemaUpgrade(object):
                 '''.format(tn=table_name, cn=column_name, vcn=view_column_name))
             self.conn.executescript(script)
 
-        for tn, cn in self.field_metadata.items():
-            if tn != 'news':
-                create_tag_browser_view(tn, cn[0], cn[1])
+        for field in self.field_metadata.itervalues():
+            if field['is_category'] and not field['is_custom'] and \
+                    field['table'] != 'news' and field['table'] is not None:
+                cn = field['table'][:-1]
+                if cn == 'serie':
+                    cn += 's'
+                create_tag_browser_view(field['table'], cn, field['column'])
diff --git a/src/calibre/library/server/opds.py b/src/calibre/library/server/opds.py
index 7c727cbf52..ca635f9c28 100644
--- a/src/calibre/library/server/opds.py
+++ b/src/calibre/library/server/opds.py
@@ -322,9 +322,17 @@ class OPDSServer(object):
             return self.get_opds_all_books(which, page_url, up_url,
                     version=version, offset=offset)
         elif type_ == 'N':
-            return self.get_opds_navcatalog(which)
+            return self.get_opds_navcatalog(which, version=version, offset=offset)
         raise cherrypy.HTTPError(404, 'Not found')
 
+    def get_opds_navcatalog(self, which, version=0, offset=0):
+        categories = self.categories_cache(
+                self.get_opds_allowed_ids_for_version(version))
+        if which not in categories:
+            raise cherrypy.HTTPError(404, 'Category %r not found'%which)
+
+
+
     def opds(self, version=0):
         version = int(version)
         if version not in BASE_HREFS: