[Pharo-users] (Kind of urgent) Phratch: operators don't work at all on last verion!

Hi all, Today we started to use phratch to a group of people without much of any experience with computer programming. The idea is to have a workshop today and tomorrow start with more symbolic and abstract approach using Pharo and give them a taste of the several levels of programmig and exploration this environment provides. But my main problem is that operators dont work on Phratch. We get a MNU as soon as we select the operators button which is a real stoper for any advance stuff. We're using the currently available package from the download page. Can somebody help me on this? Also: ¿How can we erase a line drawn with the pencil on the background? I will be sharing more questions as they come. Thanks, Offray