[funcrusher]

I had a similar problem the first time I flashed a custom rom. I was never prompted by su when running wireless tether (and i didn't know at the time), but it would still connect I just wouldn't get any internet access.

After that I went back to stock, then back to fresh and haven't had any problems since.

If it's possible, I'd try reinstalling Superuser Permissions, and if that doesn't work just re-flash.