[Zope] operation from server only?!

I've been having a problem with the YihawDirectory product for over a week and I seriously need help, going demented!. The problem I am having is that the only way for me to add EventItems is from the machine hosting Zope, when I try to do it from any of the other machines on the network I receive an error "global name 'YihawEventsItem' is not defined". I don't understand how this operation is restricted to the one machine PLEASE can someone point me in the right direction. TIA Tony