I heard about not bad application-
.dbx repair, you can use it to undelete accidentally deleted messages, move recovered correspondence to another computer or to another mail client supporting the eml message format. The tool supports files of the .dbx format for Outlook Express versions 5, 5.5 and 6, repair dbx files of Outlook Express in the batch mode, recovers information from *.dbx files up to 4GB in size, repair corrupted *.dbx files of Outlook Express greater than 2 GB in size, the dbx repair tool recovers attached files, the dbx repair tool verifies recovered messages before displaying them for the user.