client "unable to open free/busy information"

[James]

I am hoping that someone will be able to point me to a simple answer for our
problem.

We are unable to access the shared calendar for one of our users. When ever
someone other than the user trys to add or open any diary entry we get the
error message 'Unable to open the free/busy information'.

Would appreciate any clues as to what might be causing this.

Sincerely

James