Here's our situation:
The Boss is using Outlook 2007
Assistant is using Outlook 2010
Both are running XP, and both are attached to Exchange 2003
Both have Power User rights locally; neither are Administrators.

The Boss has shared her Calendar with Assistant, giving her full Editor rights
The Assistant added that calendar, and can see it.

When the Assistant tries to make any changes to that calendar, she gets an error, telling her that she does not have permissions to make changes.

I had the Boss get back into that Delegates tab, remove the Assistant, and re-Add her, again with Editor rights.

The Calendar still appears on the Assistant's calendar lists (she views several calendars - the others are all working normally).
The Assistant still cannot make any changes.

This may mean something: When the Assistant goes to File > Open, we see that the icon for "Other User's Folder" is greyed out - she could not open another shared folder if she wanted to. I'm guessing these problems are related.

Any idea what I can do to get these two things working?