Can't access 'my email inbox'

Hi

Very strange problem. My girlfriend and i both use MSN
messenger and have installed the add-in to access our
email inboxes from the program. On my computer i can sign
in as myself and access my inbox, and i can also sign in
as her and access hers....

weird thing is, on her computer she can sign in as me and
access my inbox, but not do the same with hers. She can
sign in to messenger and chat, but clicking on the 'my
email inox' link just shows a blank page. any ideas?

cheers

mark