Outlook 2007: ‘Your Out of Office settings cannot be displayed, because the

Outlook 2007: ‘Your Out of Office settings cannot be displayed, because the server is currently unavailable. Try again later

Outlook 2007: ‘Your Out of Office settings cannot be displayed, because the server is currently unavailable. Try again later.
users using outlook 2003 can configure out of office without no problem.
We are using exchange 2007.
Using out of office via Webmail works fine.
I try using this command: Set-Mailbox “brk” -ExternalOofOptions External
But it says the commands completed succefully but no settings of gorkana.local/gorkana users and groups/brk have been modifiled.
Gorkana is our domain.

Please help….. What more can i do.