Remove an http.Error() func call from an anonym func that is spawned in a separate thread because that w (http.ResponseWriter) could be not available.

internal/http/dj_handlers.go

@@ -79,7 +79,6 @@ func (dj *DJHandlers) PlaylistNext(w http.ResponseWriter, _ *http.Request) {
 		oggf, err := oggtag.NewOggFile(nxt)
 		if err != nil {
 			log.Println("cannot read an OGG file", nxt, ":", err)
-			http.Error(w, "cannot read an OGG file", http.StatusInternalServerError)
 			return
 		}