I had outlook 2007 auto archive set to archive every 7 days, but was getting an error that says “Error while archiving folder “Top of Information Store” in store “Mailbox – Name of person”. The file then the location of a PST cannot be opened.” As it shows below, then I did testing and checking settings and repairing outlook, but did not work then tried moving the PST file to its default location it worked like charm. Windows 7 does seem to have problem or permission issue writing PST to Documents. Best thing to do is put it in its default place.
You can also try is repairing Outlook, it will repair issues if its Microsoft Office related.