Registering Nook simple touch

Registering "Nook Simple Touch" is not so simple. This device doesn't work with my personal router "Asus WL500gp v2". Nook finds network, but is unable to connect neither WPA/PSK nor Open System, network is not hidden. I solved this registering Nook at my office. There is router "AP2100 Dlink" and Nook works fine with it.