The current project does not support files of this type

This error has the following causes and solutions:

• The file you tried to open is not a valid project file, or is a project file that contains features not supported by this Visual Basic host application and Visual Basic Environment.

  Make sure the project file you want to open is a valid project file (one you created and saved within the same Visual Basic host application and Visual Basic Environment).

For additional information, select the item in question and press F1 (in Windows) or HELP (on the Macintosh).