Fix .GCM file problem

I got a .gcm file for the GameCube Luigi, and when tried to rename it to .iso and burn it, I got an error saying that the file length is incorrect and refused to burn it. So I went to this site and downloaded and found the tool called GCM Fixer. I used the GUI version (FSTFiX_GUI_0.89b.exe) but it didn't work out. So I used the DOS version (fstfix13f.exe). Run it and see all the options, and then on command prompt I ran: "fstfix13f x.gcm f" to stuff the file into a 1.4Gb file. It worked great, and now I have the .iso burned properly.