As with *all* possible encryption mismatches, you should start by turning encryption off all the way 'round. Once you can connect & are able to pass traffic, then set your encryption back the way you want it.

Oh, and unless you *are* using a RADIUS server for an authentication database, you *don't* want to select that option. ;-)

There is quite a bit of discussion on this setup in the DD-WRT forums, so you might want to peruse what's available there, too.

You're making great progress, Ray. Just check your settings & be sure that when you do a wireless survey from the new router, you can see the GS. Turn on SSID broadcasting in the GS (at least for now), if indeed you have it off.