IMO, this is impossible from just uninstalling terminal...
As I said too in one of my first posts.
this sounds like either you're trying to install something that needs the Opie version of ipkg, or the file you downloaded was corrupt
I'd forgotten that people don't necessarily check for this
If you indeed cannot install any IPKs, IMO, it's practically impossible to fix given a system that doesnt have the right tools already pre-installed.
Actually it should be possibly using some of the steps I outlined above (at least it would be on particular ROMs depending on their comms setup). This is all part of the fun and why I hadn't suggested reflashing just yet ;-)
Si