Thanks to this forum post I needed to download swinglabs jar to get the Android draw9patch tool working.
Any links I found to the swinglabs main site weren’t working and the only download location I could find was via the guy in that forum who kindly hosted it via dropbox.
–UPDATE– Looks like they’ve fixed this issue in revision 9 of the sdk tools, http://developer.android.com/sdk/tools-notes.html