The user wants to delete an empty layer, but gets an error message saying "this
layer is active on the following sheets or blocks ...".
The reason for this would be that this layer is set as active in some Drawing
Views. To resolve you have to enter every Drawing View (via "Draw in View"),
and then select any other layer to be active.
After changing the layer in a drawing view, you can delete the layer.
Notes and References
OS Version: 864