Thanks, I have done so but the result is the same.
Today the R15 is totally unstable with our phones totally unable to connect as well as the E15 also no longer showing up nor being able to connect.
I suspect a reboot is in order ( have to do this every couple of days)
I had very similar issues. D-Link has released a new beta:
http://forums.dlink.com/index.php?topic=76413.msg310492#msg310492
and I found this seemed to fix everything. One thing I'd recommend is do a complete factory reset on the router - yes, I know it's annoying especially if you've set up any forwarding rules, but my R15 only became semi-reliable on the 1.3.04 firmware after I did that. The 1.04.1BETA firmware seems to fix the major issues with the Wi-Fi (though I still see occasional glitches) and all of the issues on the router side. Before I installed 1.04.1 my mobile phone, and an older laptop, wouldn't connect to it at all.
(Not a D-Link employee, just repeating the help I got in my own thread which turned out to be very useful)