But what are u expecting, when you only define the label - which artist would you get? No, dont answer "from the current song", cause this is already a part of RR. With my plugin you must first define the file which would be used for the tags and it can be any file, not just the one now playing. The command for this is:
fscommand("LOADFILEINFO;" + _root.TRACKPATH);
where _root.trackpath is the full path and name to the file.