Do PC's still have to have the file extension at the end of file names? Or have they finally gotten rid of them? If so, you need to make sure the name has the proper file extension appended to it (.doc at the end).
File extensions don't matter. If it is a file of a certain program TYPE, the program will open it whether it has an extension or not. Read this, CDogg: http://office.microsoft.com/en-us/help/HA010347441033.aspx?pid=CH010716431033 .