Problem:
I changed my computer and now the Wikipedia add-on doesn't work, it says "Composer is needed for searching Wikipedia", but i have the same songs as before i moved from pc and they used to work good. Nothing happens if i press Artist, Album, etc. I am missing a library or something?

Suggestion:
When i start a song through KRunner, Amarok adds it to the Playlist, that's good if i don't have it on it, but if the song is already there it adds it again anyway. It would be nice if Amarok could check if the song is already on the playlist so you don't have the same song multiple times on it.

You changed your computer, did you also change distribution or the version of your distribution?

As for the suggestion: there is an option to remove duplicates in a playlist, see Playlist menu -> Remove Duplicates