While working on the next video tutorial I appear to have found a bug. The drop sheets over primitives and figures are clearly okay, but when I re-created a conforming costume this caused the plugin to crash unexpectedly.
I was able to narrow the problem down to the costume mesh. The mesh must be triangulated before converting it into a conforming costume. The previous example with the Long Green Dress was triangulated but the new test costume was not.
The 0.0498 release version of the plugin removes the quads / triangle mode but this problem is more likely related to how the facet mesh moves through the modifier stack. The real cause is as yet unclear. The fix is to make sure to manually triangulate the mesh.