Thunderbird sends emails with attachments to Trash

Emails with attachments get sent to the TB Trash folder.  This happens 
on several computers running TB 1.0.5 and Mozilla 1.7.8.  This usually 
involves .doc, .pdf, .dwg, .jpg files.  However, emails with .zip files 
and a few with .doc files occasionally get through.  Yes, I use message 
filters to sort emails to folders and send emails to Trash by keyword in 
sender, subject, and body.  Junk mail controls are off.  I cannot find 
any type of filter for attachments.  Any ideas?