[Zope-dev] Product doesn't work in zope 2.7 that was working in 2.6

[MET 2004-2005]

Can anybody please help me,
Our product Named GNOWSYS is working perfectly in zope 2.6 
but when ported to zope 2.7 it does'nt get instantiated.
I guess the way we are cataloging our Objects is not correct
The Traceback of the error that occurs when we try to instantiate our product
is as follows

Exception Type          TypeError
Exception Value         'str' object is not callable

Traceback (innermost last):

    * Module ZPublisher.Publish, line 101, in publish
    * Module ZPublisher.mapply, line 88, in mapply
    * Module ZPublisher.Publish, line 39, in call_object
    * Module Products.GNOWSYS06.GNOWSYS, line 475, in addGNOWSYS
    * Module Products.ZCatalog.CatalogAwareness, line 116, in index_object
    * Module Products.ZCatalog.ZCatalog, line 537, in catalog_object

TypeError: 'str' object is not callable

is there a specific way for cataloging Objects in zope 2.7 please let us know