Sometimes it can happen that after installing the wordpress plugin called Duplicate ByeBye that you see the following error message inside the admin area of wordpress;  "The plugin does not have a valid header"

This can happen when you install the plugin from inside the wordpress admin area which won't work.

Please install the plugin the following way:
Upload the folder called cblender to the wordpress plugins folder, then activate the plugin from inside the wordpress admin area.

Also check again the installation instruction file which was included in the zip file for any other questions.