Problem
When I double-click on some file types in Nautilus, a dialog indicates that Nautilus has no installed viewer capable of displaying the file.
Nautilus
Solution
Perform the following steps:
Open the Applications menu.
Choose Desktop Preferences -> Advanced -> File Types and Programs.
Make sure the MIME type or extension for the file is associated with an application in the File Types and Programs dialog.
Make sure that the associated application is in your $PATH.