--- a/mercurial/templater.py	Tue Dec 07 22:14:43 2010 -0600
+++ b/mercurial/templater.py	Mon Dec 20 12:09:00 2010 -0600
@@ -214,6 +214,8 @@
         if not t in self.cache:
             try:
                 self.cache[t] = open(self.map[t][1]).read()
+            except KeyError, inst:
+                raise util.Abort(_('"%s" not in template map') % inst.args[0])
             except IOError, inst:
                 raise IOError(inst.args[0], _('template file %s: %s') %
                               (self.map[t][1], inst.args[1]))