[Zope] Trouble changing permission settings on file object

[paul_s_johnson@urscorp.com]

I am not able to change the permission settings on a file object.  I am
using Zope 2.2.2 on a Linux box.  I have manager status.  I receive the
following error:

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Zope Error
Zope has encountered an error while publishing this resource.

AttributeError

  Error
Error encountered while publishing this resource.

Error Type: AttributeError
Error Value: __call__

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This does not leave much of a clue what the problem is.  Anybody have any
leads?

P. Johnson