[Q] cant uninstall apps after rooting!!!

Hi all,
i have samsung galaxy pocket device,
running stock ROM 2.3.6
i performed rooting and all went on ok... got the superuser icon working and all fine..
but i cant uninstall some apps which i dont need like opera mini and chat+ for example!!!
how comes i cant remove them>??? isnt this what rooting is done for??
or do i need to do something else?
thx alot