Ah ha!
 
Thanks for finding that.
 
I updated my * server and I'm all set.
 
Many thanks for all the feedback and help.

2009/3/24 Andy Spitzer <woof@nortel.com>
Woof!

Appears to be a recently fixed * bug:

0014431: Bad branch parameter value in CANCEL request
http://bugs.digium.com/view.php?id=14431

--Woof!