The really great news is that Jim is working on a solution that will potentially fix a lot of the broken attachments, basically he has a list of what is in the database and what is in the attachment directory and he's been working on a solution to see how the hashes in the database correspond to the file names.
Hopefully a utility will be created to scan members hard drives for missing files which can be located, submitted, converted and then uploaded into the attachments directory.
In the meantime, please keep fixing your posts and posting attachments here for us to repair.