Nevermind, I was using the wrong version of 12blocks. I was still using 2.5x. It worked fine in 2.71.
So next question: has anyone tried multitasking on the Arduino via 12blocks? I came across this nifty library, ave-os, that seems to make the task easier:
It doesn’t import like a “normal” Arduino library, but I thought it would make for a neat feature (once I can get it running)…