Attachments saved as .bin files

I am using Mhonarc 2.5.13 on a Win2K platform and we often get emails with
.doc and .xls files attached.  Mhonarc generates the html for the messages
with the appropriate link name but the attachment is being created as a .bin
file.  What am I missing?
 
Thanks

Randy Blaustein 
Systems Administrator 
Armed Forces Emergency Services Center 
American Red Cross 
blausteinr(_at_)usa(_dot_)redcross(_dot_)org 
(703) 206-6799