If you want to import Motion or iMovie projects into Final Cut Express HD, you will need to have the corresponding application installed on the same computer. In other words, if you want to import a Motion (or iMovie) project, Motion (or iMovie) must also be installed on the same computer that houses Final Cut Express HD.
If the corresponding application is not installed, you will get an "Unrecognized File" alert when you try to import the project into Final Cut Express HD. To avoid seeing this message, be sure that the project's native application is installed on your target machine.