Another person w/MacTubes question

[hjkapl]

I only have OS 10.4.11. I downloaded MacTubes 3.1.6. I am guessing they are not compatible cause while I can get the player to play, the lower left button (icon) I need to use to download a file remains faint and will not do anything if I click on it.

Is there a different version of MacTubes I should be using? Will MacTubes work for me at all? Is there some other suggestion as to what software I can use to download from YouTube onto my mac that is also free (and relatively simplistic) given my OS?

Many, many thanks for any/all assistance!