I'd be happy to create a bug, but I have no idea how to do that ("TICKET_CREATE privileges are required to perform this operation", and I haven't been able to get myself over the wall of "where are the instructions on getting an account or gaining those privileges?")
Ticket creation is disabled for anonymous visitors, but enabled for all registered accounts: just use the "Register" account on the upper right.
After you do that, you may want to click on the "User Configuration" link nearby, and insert a valid email. Then, by using your login name in the Cc: ticket field, you will receive email at each ticket change.
For anonymous visitors, the "New Ticket" link is not shown; you possibly got the above error by directly going to the URL:
http://twistedmatrix.com/trac/newticket
while not logged in.