I'm very confused and need help!

I successfully setup raspyfi and the wifi using Edimax EW-7811Un according to the instructions on raspyfi.com.

I removed the network cable, mounted my NAS via Wi-Fi and immediately enjoyed my music.

The very next morning, I could not get it t work. No Wi-Fi connection. Logging in with network cable and SSH I can see the Wi-Fi networks with wicd-curses. I am connected to my wi-fi. But I could not get it to run on wi-fi without the cable. I have searched these forums and others for help and tried everything but nothing. I could also not get the adapter to work in my PC so have got a replacement.

Today, I re-imaged an SD card, inserted the new WiFi adapter and set up exactly as before. Again, i pulled out the cable, rebooted and I managed to mount my NAS drive and enjoy music – for about 30 seconds. Then the music stopped and I was unable to access http://raspyfi/ again. I could get to the command prompt via SSH wirelessly, but could not get the music to work again.

Now, I can only use the command prompt when connected with cable and can not get anything from http://raspyfi/

So. Any ideas? Have I somehow broken two wifi adapters in the same way twice? Is there something I'm doing which means that my setup corrupts every time I use it? The strangest part is that I can 'connect' to the wifi network but no data transfer is possible. Is there something wrong with the security key?

Starting again with a re-imaged SD card does not fix it. Again, I can see the wifi network and connect to it but can not access via http://raspyfi/ on cable or wi-fi. I can only access via SSH with cable.

You might be able to tell I'm a newbie to Linux and Raspberry Pi so be kind. My squeezebox broke and I wanted a challenge to create my own music player. I was extremely proud for those few hours when it did on the first day!

Setup:
Raspberry Pi model B
8MB sandisk class 10
BT Homehub 2
Synology NAS DS211j
SSH with ConnectBot for Android tablet
Edimax EW-7811Un