It seems that easm to stl conversion (or any other kind of easm conversion) is only doable if the file wasn't locked by the creator. This should be doable using SolidWorks or some 3rd party alternative, such as SketchUP Pro with the help of some plugin. If your file is locked (exported without the option to edit), you have to contact the original author of the eDrawing file and for export to some other format from the original source.
Open EASM file Open STL file