Looking at Office MS Access I found something that may help? When you need to update or edit a link you need to do the following:
To update unbound images, in the Database window, select the form or report that contains the unbound object frame, and then click Design . To update bound images, open the form or report for viewing (or open the underlying table in Datasheet view), find the image link that you want to change, and click it. 2.On the Edit menu, click OLE/DDE Links. 3.In the Links dialog box, click the link that you want to reconnect or change. 4.Click Change Source. 5.In the Change Source dialog box, select the new file name. You may need to switch to a different drive or folder or both to find the appropriate file. 6.Click Open to complete the link and close the Change Source dialog box, and then click Close in the Links dialog box.
This may help you track down were the document is stored?