[Zope] zlib.error : huh?

[Aaron Straup Cope]

I am trying to understand what exactly is going on when Zope returns an
Error -5 page.

Normally, this only happens on the left hand navigational menu but today
it happened while I was expanding an xml document/tree object from the  
Examples package for the XML Document product.

I've tried searching Google, the Zope site and the mailing list but to no
avail. Could someone please explain what's going on here? Is it me? Is it
Zope? How exactly do I prevent these errors from happening?

Thanks,

Error Type: zlib.error
Error Value: Error -5 while decompressing data: []

Traceback (innermost last):
  File /usr/local/zope.old/lib/python/ZPublisher/Publish.py, line 222, in
publish_module
  File /usr/local/zope.old/lib/python/ZPublisher/Publish.py, line 187, in
publish
  File /usr/local/zope.old/lib/python/Zope/__init__.py, line 221, in
zpublisher_exception_hook
    (Object: Traversable)
  File /usr/local/zope.old/lib/python/ZPublisher/Publish.py, line 171, in
publish
  File /usr/local/zope.old/lib/python/ZPublisher/mapply.py, line 160, in
mapply
    (Object: tree)
  File /usr/local/zope.old/lib/python/ZPublisher/Publish.py, line 112, in
call_object
    (Object: tree)
  File /usr/local/zope.old/lib/python/OFS/DTMLDocument.py, line 177, in
__call__
    (Object: tree)
  File /usr/local/zope.old/lib/python/DocumentTemplate/DT_String.py, line
528, in __call__
    (Object: tree)
  File /usr/local/zope.old/lib/python/TreeDisplay/TreeTag.py, line 154, in
render
    (Object: test[0])
  File /usr/local/zope.old/lib/python/TreeDisplay/TreeTag.py, line 229, in
tpRender
    (Object: Manageable)
  File /usr/local/zope.old/lib/python/TreeDisplay/TreeTag.py, line 637, in
decode_seq
zlib.error: (see above)