Hi,
i'm having the same problem. My led on 2.4 Ghz band is not working, the 5 Ghz and wired ports works well. I'm sure the 2.4Ghz is broadcasting, because i can see it in inssider!
i'm using the stock asus 3.0.0.4.260 firmware. the router is about 3 weeks old now. probably it is a bug or...