Background

The new version of the MediaPortal Extension Installer (MPEI) applies to MediaPortal versions 1.1.x and later.  It uses a file extension .mpe1.  The old version MPInstaller (which still exists in MediaPortal for backward compatibility) uses .mp1 files.

Answer

Normally you may install an extension by just double clicking the file. However, in some cases you may need to associate the file extension with the correct version of the Extension Installer.

When using MPEI, you may also receive an "Wrong File Format' error when double clicking a .mpe1 file when files in your %temp% folder have been corrupted, often due to a bad internect connection.

In this case, just delete the files from your %temp% folder and this should resovle the problem.

If this does not resolve the issue, you may also rename %programdata%\Installer\V2 folder, however, you will then need to refresh all data for the MPEInstaller browser.