Install synaptic with
Code:
sudo apt-get install synaptic
and then see if you can use that to install packages you want.
If you already have the packages downloaded try installing and using gdebi, which you may find tells you more than USC.
Either way, I would suggest that synaptic and gdebi are both worth adding to any new install of the *ubuntu family of OSs.
I have no idea what you mean by app grid.