MS Outlook 2003 email forward & reply not functioning.

Recently i am facing a problem which, my MS Outlook not allow me to forward & reply the email that i had received. Once i press for Forward or Reply button, the message will show “The Operation Failed”.
After i click ok to quit, the subsequent message show “The operation failed due to an installation problem. Restart Outlook and try again”. In fact i have close & open again. Even re-install the office, but it doesn’t help.
I have no idea why it happen. Please help.