adb devices was working fine last year, but after upgrades and new software installs, adb devices no longer recognizes USB attached Android devices.
adb devices
Her
I have the same problem, I solved using an alternate install method.
First I put an sd card in my device. Then I use a File Manager to transfer the .apk to the device, and I install it from the device
You can see a tutorial in http://www.youtube.com/watch?v=7UOAw124y1s