New to the DrupalED -> GOOD but now I have problem with the creation of GROUPS

New to the DrupalED -> I have installed the last version, with catalan, all is running absolutelly perfect
GOOD but now I have problem with GROUPS. I can not create news groups what have we to do?

I think that it will be a good idea to do a list of modules running well and not? e.g. Scrolltext is perfect but the stringoverrides not