[Pharo-project] Problems with SmaccDev and Pharo

Hi all, My name is Oscar. I've been working with Pharo trying to do a gradual type system. Part of that is working with a Parser for a specific type annotation that I have. I'm using: *Pharo1.0rc1 Latest update: #10492 *SmaCC-lr.13 *SmaCCDev -lr.21 But I have some problems when I use SmaCCParserGenerator window, because I cannot select any option (there are some arrow pictures instead of check-buttons) and always get the error: MessageNotUnderstood: RBClass>>metaclass Does someone has either a suggestion or solution? (sorry If this is an easy/stupid problem) Greetings (I apologize for my poor english) Oscar E. A. Callaú P.S.: I attach a picture about the problem.