[Gabriel Luke]

The drop shadow in inkscape, like most vector applications I know of, is a raster effect or a bitmap when it has a drop shadow. All paths are required for the vinyl cutter, so it can not operate with a bitmap. A drop shadow is also a raster effect as it gives it a natural look as it is blurry around the edges. Fuzzy, which is all straight line, does not fit well as cut vinyl. If you want a solid block or shape, just draw it as a shadow. Alternatively, you can work with a replica of the main form and distort it such that it is inverted and / or upside down or angled to whatever scale you want a shadow to imitate. Only catch the edge of the copy and begin to drag it.