You may want to check your power supply and try putting the wifi module on a powered hub. I had an issue where I wasn't using a good power supply and it kept dropping connection.
i am using a powered hub. i think i have messed up my config files for this. tired following so many different sources and lost track of what i did. Still no wifi for me
And the wpa_supplicant.conf ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ctrl_interface=DIR/var/run/wpa_supplicant GROUP=ntdev update_config=1 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
To be honest, I don't know if these are the original ones, because I fiddled around with a FRITZ!WLAN an old DLink and a Netgear USB stick - but my Edimax is working with those files and the WLAN_GUI (Most recent PiMame 0.8b2 updated, 1A PowerSupply, no USB Hub, just WLAN and wireless receiver for KB/Mouse connected).