PrintPlus,
You cannot upload a Word document to appear in your PrintShop Mail document via PrintShop Mail Web. You can import a .doc file and it will be converted to pdf from PrintShop Mail, but PrintShop Mail Web will not do this automatically. What I suggest is that you convert the Word documents to pdf manually, which can be done if you have Acrobat(Standard or Pro version, not Reader), and then upload those pdf files to PrintShop Mail Web. As a pdf, you will be able to upload the files and use them just fine.
Hope that helps!
Regards,
Raphaël Lalonde Lefebvre