LayerSlider not installed + purchase code

Hi,
do you have the purchase code for the layerSlider for me?
just installed LayerSlider but Theme says:

This theme recommends the following plugin: Layer slider.
Begin installing plugin | Dismiss this notice

But i can see the slider in the menu. Whats wrong.

When i try to install it again it says something like “the plugin folder already” exists and Das Plugin hat keinen validen Header (the plugin doesn´t have a valid header).

Plugin install failed.

Thanks in advance