[PROBLEM] No networks show up while scanning

[ADeda]

Hi,

I am stuck with the following problem:
Recently I installed Xbian (RC3) on my Raspberry Pi. I also bought a Wi-Fi adapter (one of those no-branded-ones) to connect to the Wi-Fi network at home. When I try to connect to a network (via the Xbian settings) I select wlan0 instead of eth0, and then I click on SSID. A popup saying 'scanning for networks' shows up, and then a screen comes up, showing nothing. I have also tried scanning for networks through the xbian-config, but that doesn't work either; no networks are displayed.

Since the Wi-Fi adapter works and is recognized, I don't know what could be the problem. So, could anyone help me sort this one out?