[Zope] Zope 2.5.1 import error on Red Hat 7.3

[Andrea Bacherini]

Hallo,
we have import error with some zope plugins.
This is a Traceback :
Traceback (most recent call last):
  File "/home/Zope/lib/python/OFS/Application.py", line 531, in
  import_product    product=__import__(pname, global_dict, global_dict, silly)
  File "/home/Zope/lib/python/Products/GUM/__init__.py", line 38, in ?
    import gum
  File "/home/Zope/lib/python/Products/GUM/gum.py", line 31, in ?
    from ZPublisher.HTTPRequest import html_quote
ImportError: cannot import name html_quote

 ... Have you any idea?
 Thanks