What version of PathPilot?
Please expand on how you are "editing in the on-screen FILE editor"? Are you clicking the "Edit G-Code" button which brings up the file in gedit, selecting some text, and then using the clipboard functionality to copy/paste from one file into another?
Or are you using the conversational editing features of PathPilot?
Can you supply a snippet of the gcode file showing an example of the "quirky symbols"?