The inbox.dbx file might be partially corrupt. Have you tried closing OE
and then rename inbox.dbx to inbox.old? (OE will start with a new inbox.dbx
file. From there, create a new folder call "Recover". Close OE and then
delete the recover.dbx file. Rename inbox.old to recover.dbx. Start OE and
see if you can move/copy items from Recover to Inbox. When finished, delete
the recover folder.)