I had the same problem.
PROCESSING 2.0b7 (REV 0215) - 7 December 2012 475,382 bug fixes in this release as we work on finalizing 2.0. [ changes ] + Removed all imports that aren't covered in the Processing reference. If you use java.awt, java.util, or other classes in your sketch, you will need to add an import line to the beginning of your sketch.
Solution
Put this line on top of the program
- import java.util.Calendar;