free/busy error for sharing calendar rights

After I installed MS 2007, I did not have access to my boss' calendar. I
could vew it, but not do any changes or additions to it. I'm getting an
error message "Cannot open the free/busy information. You do not have
sufficient permission to perform this operation on this object. See the
folder to contact or your system administrator. I have "owner" rights on my
boss' end, and have done all my updates to the computer, I have added the
rights - re-booted on both ends and added rights again - but this still
doesn't allow me access. HELP!