[Evolution] No provider available for protocol 'exchange'

[<Carlos Guerreiro nokia com>]

Hi all,

I'm using Evolution 1.2 on a RH8.0 system with Ximian Connector 1.2
I used to be able to access folders on an Exchange server without problems until after I shutdown my machine 
for the weekend.
When I try to open a folder I get error messages like:
"Error while 'Opening folder exchange://user server/personal/Inbox':
No provider available for protocol 'exchange'"

Evolution can still list the folder tree and update the unreaded emails count as I receive emails.
I suspect something might have got broken in my Evolution configuration. What should I look for?

Sending email fails with a similar message.

Best regards,
Carlos