>Now I'm getting something better than this, but... It works with the spaces in some parts of the filename, it's just the server name that can't have spaces (which I haven't actually seen) and the share name. If there are no spaces in the share name, I can put as many spaces as I like in the filename and along the path. Anyone with something fresher than this?

The story continues... I got the share renamed from "D drive" to "D_drive" but it still wouldn't work as long as I had spaces in the path (which it was willingly allowing on a local drive). So it seems to be spaces in an UNC path are a mortal sin (your exe does die, doesn't it?) and they're still OK if you have a drive mapping or a local drive (tried and both work, including spaces in path and in the name of the executable).