Can you retrieve an attachment email? I understand according to the knowledgebase that sometimes there is a problem with emails attaching to history properly and can be fixed with the Hotfix. However, the knowledgebase did not indicate if we could retrieve the missing attachment at all?
Just guessing, but maybe it's still in the attachments folder but no longer linked to the history. For sake of explaining, while in ACT just go to Write, Other Document, go up one folder, select the attachments folder, and in the File Name type *.* then press enter. If you can't find it in there, it's probably gone.