Thx Patrick & Tully, I got this problem by installing the ROS-only install and then installing only the packages that I needed one by one. Finally I got crazy and erased and reinstalled everything with the base install through svn in my debian machine and now everything seems to work properly. I don't know that much about the cturtle concept, as I am a beginner in ROS, so i guess now I'll have to learn better about it :). By the way... what is Diamondback :? Besides that, thx for ur help and I think ur doing a great job with ROS! Josep!