I can't run your file (I've only got Express--no programming), so this is only a guess, but I'd suspect that the root function is failing to find a root.
Might want to see if you can localize that issue, and/or wait for someone with full Prime to take a look.
An impressive work!
Just a tip: You can change the font size of just one math entry (like your program) to make it fit to the page just a bit better. Select that entry, then math formatting and font size. Adjusting this without selecting an area may change ALL of the math areas.
