This affects all versions of dbFM. The file manager was designed from day one to only upload files with a file extension. This allows features such as being able to block files with certain extensions. It's also very important for dbfmsearch - the file extension is used to determine which converter to use so that the document may be indexed. Without a file extension your OS will not know how to open or deal with a file.
However ... users have requested that the ability to upload documents with no extension be added. I'll give some consideration as to how this might be achieved.