Ah no, No popup error messages! I can access the file by using Notepad and then after removing and replacing the text, I save it. But after reopening the file, there is no change in text, like nothing was ever done.
I copied the file from the Retrode to my hard drive and edited the text, this worked fine, which is understandable. =)
Looking around for a CFG editor that I might understand atm.
Edit: Downloaded "Cubepad", might work...
Edit 2: Nope, Cubepad can't edit it, only open and "fake save it", as with Notepad.