diff --git a/hggit/git_handler.py b/hggit/git_handler.py
index b69bda29e65cfa02ad077f5096c8e7acbadcf820_aGdnaXQvZ2l0X2hhbmRsZXIucHk=..19f201d64a16fa90805560e0081508b49c447e40_aGdnaXQvZ2l0X2hhbmRsZXIucHk= 100644
--- a/hggit/git_handler.py
+++ b/hggit/git_handler.py
@@ -584,7 +584,7 @@
                 for h in heads:
                     r = [ref for ref in refs if ref.endswith('/'+h)]
                     if not r:
-                        raise hgutil.Abort("ref %s not found on remote server")
+                        raise hgutil.Abort("ref %s not found on remote server" % h)
                     elif len(r) == 1:
                         want.append(refs[r[0]])
                     else:
@@ -588,7 +588,7 @@
                     elif len(r) == 1:
                         want.append(refs[r[0]])
                     else:
-                        raise hgutil.Abort("ambiguous reference %s: %r"%(h, r))
+                        raise hgutil.Abort("ambiguous reference %s: %r" % (h, r))
             else:
                 want = [sha for ref, sha in refs.iteritems()
                         if not ref.endswith('^{}')]