I've used kai for about 6 years (before 360). You don't need a jtag to use it, you don't even need a 360 (it can even be a PSP, xbox1, etc...). So, what you should try to do is just get it working with 2 normal xbox's (with or without dvdrom mods matters not). Then, install the patch and see if it was really the patch. 8 times out of 10 it is a firewall. The other 2 times it is because you didn't read the manual for kai (you forward port 30000 to your PC's ip, _NOT_ to your xbox's ip). Also, there is a configure tool for kai in the install directory, it doesn't actually have to be port 30000. It works for the old kai client and the new we based one. Also, some virus programs can actually get in the way too, just in case you have a overbearing virus program, might want to check that.
Again, get it working without the patch, then try the patch.
Off Topic: I have a post in the dash launch thread about my xbox continuously rebooting right as it tries to load the dash, any help is welcomed. I would like to try kai with people farther away. And being you have to have dashlaunch installed correctly, I cannot do that. Unless, there is a way to apply the patch without dashlaunch?