Quite different meanings: a) non posso fare XYZ I cannot do XYZ (I am not capable of, I don't have permission to) b) non ne posso piu` di XYZ I cannot stand anymore XYZ /ne/ is quite a difficult multiple-use particle, in this case it is necessary, but for now I think it is better that you see (b) as an idiomatic expression, as it actually is. c) non posso piu` sopportare XYZ same meaning as (b), but not in idiomatic form. Usually we use /b/, unless the context is very, very formal.

"non ne posso più" means "I can't take it anymore", or "I can't take anymore of this". You could therefore translate "ne" as "of this". As Andrew says, "non posso" and "non ne posso" have very different meanings. Non posso più giocare = I can't play anymore Non ne posso più di giocare = I have had enough of playing. I hope I have not confused you...

Why in he Spanish section ?