Key layer_type, file is missing in in the plugin definition of the layer type openlayers_layer_type_MY_MODULE. The layer will be

I am getting this error.

Key layer_type, file is missing in in the plugin definition of the layer type openlayers_layer_type_MY_MODULE. The layer will be disabled.

On this page on my site.
https://www.purtle.com/testimonials

How do I eliminate it?