I have it installed and it basically works great, except on a few song it will give me an error. It says, Encoding: iso-8859-15. I don't know what to do about it. It finds the lyrics even when it shows the error, but it wont simply start moving like the other songs.

First check whether it is .txt or .lrc lyrics file. If it is .txt then it would not scroll unless you enable option Enable Scrolling (No timestamp). Then try to search for the lyrics manually. Maybe it just tries to download broken lyrics.