Photo Contest- will not install

Just bought photo contest. I will through the WP Plugin install process. It will not intall. Below is the only messaging I get. Please help me to get this installed.

Unpacking the package…

Installing the plugin…

The package could not be installed. No valid plugins were found.

Plugin installation failed.

Thank You, Allan

Install only the plugin folder and not the entire download which probably includes documentation etc

Thank you. That worked!! I appreciate your quick reply.