Outlook 2003 error "The messaging interface has returned an unknown error if the problem persists restart outlook"
 

Hi,
I am not able to perform actions like ReplyAll, Updating a task item..
on my outlook 2003, am getting the following error - The messaging
interface has returned an unknown error if the problem persists
restart outlook.

Prior to this installtion i had outlook 2007 beta installed on my
machine but I uninstalled it, actually during the uninstall process i
had accidentally clicked the cancel button, later on i did the
uninstallation from Control Panel.
Then i tried installing outlook 2003 though the installation got
executed smoothly but am not able to perform the above mentioned
actions.
Also as a repair mechanism I had run SCANPST.exe on my .pst folder
without any success.
The size of the .pst file is 14.5 MB on disk.

Can anybody please help me out of this.

Thanks and Regards
Naresh