I have the same issue. Set the password, rebooted the router, and couldn't get in. I tried a blank password, but that didn't work. Had to reset the router completely. I have kept the password blank because I'm afraid it will just happen again.
Not to mix issues here, but I'm also experiencing the problem where my connections max out at 65/72 Mbps, even after following everything in the sticky. I think having access to the 20/40 MHz Coexistence setting might help (as someone posted in another thread).
Anyway, could I please have the link to the Beta firmware? I have hardware revision A1 (is there a newer revision?)
Cheers!