I have no trouble re-ordering playlists.

In version 2.0 beta 11, Alt-dragging the playlists works for me. In version 1.03, I think there were up and down buttons available.

Make sure that you're in View/Details mode, make sure you can see the "position" column (activate it if you have to), click on the column header to sort by position, and select the parent "playlists" folder in the left-hand pane. Then, in the right-hand pane, alt-drag the playlists.

Like I said, works for me...