Actually this did not run as well as expected. I've got a very high rate of rejected (about 10%) and after running for two hours phoenix stalled again:

Traceback (most recent call last):
  File "phoenix.py", line 125, in
  File "twisted\internet\base.pyc", line 1162, in run
  File "twisted\internet\base.pyc", line 1171, in mainLoop
--- ---
  File "twisted\internet\base.pyc", line 793, in runUntilCurrent
  File "minerutil\RPCProtocol.pyc", line 127, in callback
  File "minerutil\RPCProtocol.pyc", line 319, in handleWork
exceptions.TypeError: argument of type 'NoneType' is not iterable
[23/05/2011 01:04:42] Result: 4b18edf7 rejected

My connection has some packet loss (~2-4%) but the latency in general is good (under 150ms). Could this be a problem?