Please try to update SugarJ to the latest version and then check again. The current version is 184.108.40.206307181446, so the update is from today, 14:46 CEST.
I use a fresh Eclipse SDK (Classic), v4.2.2, Build id: M20130204-1200 with only the above version of SugarJ as plugin and can not reproduce the problem.
You can also try to create your own Java application launch configuration in Eclipse and just specify atm.Machine as Main class.
And then of course the hints from WebLab, using Project -> Clean, and deleting the .*cache folders in the project directory.
Good Luck getting it running!