Thanks for your response! There aren't any error codes, it basically just doesn't load. The code is there, but it doesn't load any graphics. If I try to run it, it does nothing. I use MeshCam for the 3d toolpaths, and I asked Robert, the developer of Meshcam about it. I sent him some sample files and he couldn't find anything wrong with them. He thought it must have something to do with the Mach4 install or settings, but I don't know what that would be. This forum post is my next step.