Hmm the problem is that when a skin is compressed in zip format, the file names are converted to lower case when extracted (I did that to solve issues with winamp2 skins). But as you wrote "iPod.png" and not "ipod.png" in theme.xml, the file cannot be found on linux as the file system is case sensitive.
Please always use lower case to avoid problems...
I've just uploaded a fixed version of the skin on videolan.org and it works fine now