Outlook Contact folder can't be opened

My outlook contacts just “started hiding”. I can go to the folder and see and/or change any entry, but when I try to insert an address by clicking on the To: button I get the following message:

“The address list could not be displayed. The contacts list associated with this folder could not be opened; it may have been moved or deleted, or you do not have permissions. For information on how to remove this folder from the Outlook Address Book, see Microsoft Office Outlook Help.”

Any ideas would be gratefully appreciated.

Running Win XP Pro SP2, MS Office Pro 2003 and I am the administrator, so permissions should not be a problem.

I am not dumb enough to say nothing has changed, but I don't remember changing anything.

 

In Outlook, if you click <View> from the top toolbar, then <Options> in the drop down menu.....a box appears. Click <contacts> second button from the bottom...in the box that then appears, is the <Look in:> set to your Contacts folder, and those contacts shown in the lower half of the box?

 

Ok, I went to View -- No *Options* choice. There is one in Tools, and contacts is in the second row from the bottom, but ALL it asks is Name order, and sort order. No location referenced. (This is Outlook 2003).