Classic Cannot connect to B&N shop over wifi

[pienjo]

Hi,

I have a strange problem. My nook doesn't seem to be able to connect to the B&N store. Whenever I try to "check for new B&N content" I get an error, telling me to check my connection settings. There's two things that I don't understand:

1) The webbrowser works. Apparently my wifi works. (and needless to say: It works just fine for other devices)

2) If I connect a *second* router behind my own router, everything works! So at the very least, I know it's unrelated to my IP or anything. I also know that it's not necessarily my own router per se..

Now, my router (the first one, so to say) is a roll-your-own; a NetBSD-based router with an Atheros network card. It's using WPA2, using either WPA-PSK with TKIP and CCMP ciphers. There's no firewalling involved. Wireless and wired local lan are in a bridge - and the wired connection apparently works.

Any idea what I should be looking at? What can cause the B&N shop to fail, while the webbrowser works?