I just had a look at mine running v23 SP2. I am only using WPA, not WPA2.

From memory I couldn't get it bridge properly when using WPA2. I was happy enough with just WPA. So that might be the issue you're having although you're running an even older firmware version.

I'd be at least upgrading to v23 SP2 or try that v24 version Mark suggested. You said you're running v23 SP2 but the screen shot you gave shows only v23. It should say "DD-WRT v23 SP2 (09/15/06) std - build 3932"