I flashed cacko 1.23 to my C1000, got a working CF card, but when I went to connect to the internet, I found out that the network wizard doesn't work. When clicked the setup button, it tells me that the setup assistant is not installed (or something like that, my Japanese is a little rusty). I manually added my router to the list, but the connect button is greyed out, so I cant get it to connect. Any ideas on how to fix this?

I think you will have to reflash. Seems like something went wrong.
Then, under settings/network, click on wifi, then click "add" and enter details of the connection.

Check here for information about the internet wizard. To configure any network interface, choose the type of interface first (in your case Wireless LAN Card), click "Add" and configure your settings - then you should be able to connect.