Not at all. No previous Mathematica training is required or expected. Students learn to use the Mathematica code gradually as they progress through the courses. The overwhelming majority (85% as measured by survey) of new C&M students with no previous Mathematica experience report they are comfortable within two weeks.
I wouldn't be doing this stuff [at Pixar] if it weren't for those classes. It's all math and working together with other people.
Techs support both the lab machines and the software used in this program.
In the event of a problem, send an e-mail to tech@cm.math.uiuc.edu.