At first blush this looks like a scope issue.
http://www.lua.org/manual/5.1/manual.html#2.6
I'm a bit curious of the need for 60 separate local variables being accessed on each frame update. You also should take care of creating new locals in each update as well, as it appears that your goal is extreme performance. Though I would offer the advice that getting it working with a table at first and then going back and optimizing the most often executed code wouldntield better or at least more timely results. Just my $.02. I could be wrong.