Mail garbling attachments-help please

I've begun using Mail.app in 10.2 but I am having one problem. Intermittently attachments come through as garbled text in the body of the message, instead of as attachments. These are primarily just Word files. The problem seems to mostly happen when the email is routed through my school's groupwise system. I can download the same emails with eudora and the attachments are fine; I can even then email the same attachment to myself (using eudora) and receive it with Mail just fine. It seems like the problem might just be that sometimes Mail.app is not recognizing the attachment as an attachment. Any suggestions on how I can force Mail.app to recognize attachments, or otherwise solve this? Thanks