I'm a pretty novice MAC user. Does anyone know how to 'undo' the terminal commands I typed in to try that fix?
You can't just 'undo' terminal commands in most cases (but there may be an inverse command). It depends on the exact command you have executed, so you need to be more specific.
Also, with regard to this, the shadowandy method detailed here: http://www.shadowandy.net/2011/08/time-machine-on-lion-with-dns-320.htm
...it works perfectly. There are just a few CNID warnings - so look in the comments and you will see I've posted a way to get around the CNID warnings. Result = 100% working TimeMachine as in Snow Leopard.
This is the best solution for now, any solution that involves modifying Lion itself may result in compromising security.
The official DLink update will be most welcome, but also, you may be waiting for a while!