Great looking plugin. This would be immensely practical for a few projects i've got sitting around.
I gave the 0.6.3 and also the last stable version a try on my mac and can't seem to get it to work. I'm running Sketchup 8.0.11751 on a Mac.
I'm having a similar issue to bigstick. It's creating the paths and generating spots for leaves, but wont actually create the volumes.
Keep up the good work! This one's a winner.