I've made some minor changes to your code. In fact I've added a few properties to your layer:

    isBaseLayer: true, 
    wrapDateLine: true,
    maxExtent: new OpenLayers.Bounds(-180, -180, 180, 120)

And **[here][1]**'s the whole code for you, to easily test it. Just unzip the file, extract the *scrobbler.html* file and double click it.

Just zoom out and move the map, as you like.


  [1]: https://dl.dropboxusercontent.com/u/13060205/Stackexchange/Skobbler/skobbler.zip