Cannot open assigned task in Outlook 2003

[Robert]

At home, my wife is using Outlook 2003 on a XP Home SP2 PC.
I use Outlook 2003 on a XP Pro SP2 Notebook.

When I assign my wife a task from my notebook it comes into her Inbox and
she can see it in the preview pane, but cannot open it when double-click it
and cannot accept or decline it thru the preview pane.

We have NO Exchange server between us.

I can assign tasks to others in my company via that Exchange server and they
go through just fine.

My wife can assign tasks to me, from the home computer, to my notebook, and
they work just fine that direction.

Thanks,
Robert