OL2003:This item cannot be displayed in the preview pane

Hello outlook Gurus!
I started recently getting these messages in my outlook 2033 preview
panel on random emails and very common emails. The message is: “this
item cannot be displayed in the preview pane, open this item to view”
and the preview pane shows nothing but this message. When I click on
the email, i can read it, though. Also if I close outlook and start it
again, i can even preview the email, which was not previously
displayed.
it started happening recently and bugging me very much.
please help!