[Zope] Problem with management interface.

I maintain a Zope application that basically doesn't need any maintance ( lucky me!) However a problem crept up so I went to look via the management interface ...../manage To my suprise I did see the familiar tree in the left frame but on the right I did not see the contents of the rootfolder but the folder as if a had not typed .../manage i.e the rendered index_html. Does anyone have an idea what is going on? Thanks in advance for any clues. I use Zope 2.3.1 (binary release, python 1.5.2, win32-x86)

Wim Stolker