[Twisted-web] Strange Nevow / Athena error

[Paul Reznicek]

Hello,
I observe this error few times a day and have no idea about what is causing
it, neither under which conditions it happen (Nevow-0.9.33):

Traceback (most recent call last):
   File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 195, in addCallback
     callbackKeywords=kw)
   File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 186, in 
addCallbacks
     self._runCallbacks()
   File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 328, in 
_runCallbacks
     self.result = callback(self.result, *args, **kw)
   File "/usr/local/lib/python2.6/dist-packages/nevow/appserver.py", line 163, in 
gotPageContext
     pageContext.tag.renderHTTP, pageContext
--- <exception caught here> ---
   File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 106, in 
maybeDeferred
     result = f(*args, **kw)
   File "/usr/local/lib/python2.6/dist-packages/nevow/athena.py", line 440, in renderHTTP
     messageData = json.parse(requestContent)
   File "/usr/local/lib/python2.6/dist-packages/nevow/json.py", line 228, in parse
     value, tokens = parseValue(tokens)
   File "/usr/local/lib/python2.6/dist-packages/nevow/json.py", line 130, in parseValue
     if tokens[0] == '{':
exceptions.IndexError: list index out of range

I asked some user, but nobody observed problems on the user site,
any idea, what is wrong?

Regards, Paul