Ok so I figured out why my themes don't work on my 3G 4.2 OS. The next question is, which themes exactly do I now DL? A spattering of themes like iFusion has been updated for users like me, and I don't know if I'm supposed to search thru the iPhone 4 themes or not. I DL the Vivid Theme listed with the ones from the button on the front Cydia page, but that one doesn't work.
HD or not to HD...

Is there perhaps a section of 3G/Gs themes updated to work on anything 4.1 or later?