Searching at http://support.microsoft.com, a huge knowledgebase provided
by Microsoft, on "object not found" with "Outlook" selected as the
product (since you did not specify WHICH version you have), returned:
Also, try disabling all plug-ins to Outlook that you installed (except
for the Exchange add-ons if you are using Exchange as the mail server):
Tools -> Options -> Other -> Advanced -> COM plug-ins or Add-Ons. Also
try starting Outlook in safe mode ("outlook.exe /safe") to see if the
problem goes away.