I am trying to learn pyx ans started off with the hello world example but I get a error message.

Traceback (most recent call last):
  File "junk1.py", line 4, in <module>
    c.text(0, 0, "Hello, world!")
  File "/usr/lib/python2.5/site-packages/pyx/canvas.py", line 308, in text
    return self.insert(self.texrunner.text(x, y, atext, *args, **kwargs))
  File "/usr/lib/python2.5/site-packages/pyx/text.py", line 1197, in text
    self.execute(expr, self.defaulttexmessagesdefaultrun + self.texmessagesdefaultrun + texmessages)
  File "/usr/lib/python2.5/site-packages/pyx/text.py", line 989, in execute
    self.expectqueue.put_nowait("PyXInputMarker:executeid=%i:" % self.executeid)
  File "Queue.py", line 145, in put_nowait
    return self.put(item, False)
  File "Queue.py", line 120, in put
    raise Full
Full

Are there dependencies?  I am using Ubuntu 7.10 (gutsy) and idle.