Your last post did not mention that the extras repository was present; that's a category, and it's only by confusing accident that they have the same name.

You need to go into the menu, choose Tools, choose Application catalog..., and make sure you have a repository (probably named "maemo Extras") with the web address http://repository.maemo.org/extras, and components free and non-free. (And enabled.)

Maybe you already did that, but your last post referred to something else, and you say "as mentioned in my last post", I can't help but think you still haven't quite got it right.