mkisofs -o file.iso -b isolinux.bin -c boot.cat -no-emul-boot \ -boot -load-size 4 -boot-info-table -R -J -v -T isolinux/
Looks like you have an escape character sequence in there "\" Are you sure it shouldn't be a "/" instead? Try it again changing that character in your command. if you are trying to purposely use a back-slash you may have to put it in twice "\\" to be able to use it because generally it is used as the escape sequence character. (i.e. say you had a filename with a space in it, "some file.txt" you access that file from the command line as "some\ file.txt", the backslash tells the shell that an... odd character is coming next which would be the space and the backslash is used to notify the computer of this).
mkisofs -o file.iso -b isolinux.bin -c boot.cat -no-emul-boot / -boot -load-size 4 -boot-info-table -R -J -v -T isolinux/
and see what happens... then again, I could be completely wrong here.. which I would blame on lack of sleep