[Pharo-project] Loading GemTools in Pharo 1.1.1-dev

Hi, I want to try GemStone. So I started loading GemTools in a Pharo image 1.1.1-dev without success. An error appears when loading Metacello Browser version #development. After that I tried to load first MetacelloBrowser and then I got the same error for OmniBrowser version #stable. What am I doing wrong? or do I need to use a different image? Regards, Veronica