[Zope] ERROR BeforeTraverse Error while invoking hook

[Maciej Wisniowski]

Hi!

After upgrading our Zope instances from Zope 2.7.2 to 2.8.4 we've noticed
new kind of errors in event.log on one of our servers. Error is as follows:

2005-12-19T07:53:59 ERROR BeforeTraverse Error while invoking hook: "input"
Traceback (most recent call last):
  File "/opt/Zope/2.8.4/lib/python/ZPublisher/BeforeTraverse.py", line 
144, in __call__
    meth(*(container, request, None)[:args])
AttributeError: __call__

I've looked into BeforeTraverse.py and I see this error is only logged 
to event.log and
is not visible to the users, and it seems to me that it is something 
with acquisition(?)
I need some hints how to find what causes this error - what has changed 
in 2.8.x and
how to deal with this?
Our application is written in ZODB not in products. There is a folder 
named 'input' in it,
may it be the problem?

-- 
Maciej Wisniowski