Try enclosing your filename and directories within quotation marks. You've got spaces in the "normal map converter" folder name, which'll be throwing off the command line interpreter. Quote marks will let it read the entire directory and filename as one input.
Hey Fozi, I've had very little time to try it out, but I really like it so far, thanks again:). As for the GUI, I've made my own very quick GUI to make it easier for me to test this thing out, so if someone wants it until Fozi wraps it in a nice looking and easy to use GUI, here it is:…