When I first installed Attachments is worked beautifully. Then when I updated from Joomla! 1.5.11 to 1.5.12 it quit working. It turned out to be a problem with 1.5.12 not Attachments.
The Joomla! project group quickly fixed the problem in 1.5.13 and later, but for some reason I couldn't get Attachments to work.
Jonathan responded to my email and offered to take a look at the problem if I would provide him with a temp superadmin login and a temp ftp login on my server.
He logged in and made adjustments to my .htaccess file and changed the allowed file upload size. Joomla!'s default is only 2Megs and my files were larger than that.
Thanks Jonathan for the awesome support. Wow!