LW format ... what DO you mean!? LW does not DO formats! Using mac 8.6 might well limit your ability to play everything available as hardly anybody produces software for it any more.
You do not mention the file types you are having problems with.
If you get a file that cannot play, you will have to find an 8.6 compatible programme to convert it to a file type you can play ( you could always update to OSX)
