Could not change to that identity – Outlook error after reinstalling

After installing and later reinstalling Microsoft Office for Mac 2011 on my new MacBook Pro, my Outlook worked fine.

However, yesterday I reinstalled again using the same DVD on the same computer and Outlook now no longer works.

It says: “Could not change to that identity. An unknown error has occurred in Outlook”.

When I press "OK", it then tells me to "Select an identity".

There is only one identity showing, which is "Main identity".

When I press "OK", it goes back to the previous error message, and so on, backwards and forwards between the two messages, and Outlook never opens.

Can anyone help? Thanks.

Jonathan

Question about Outlook Express