Failed to install due to Timeout in Emulator
If its timeout then may be ADB connection with the eclipse will need more timeout limit. So Try this:
Prefrences>android>DDMS and you will see ADB connection timeout extend it to 20000
When this happen's to us on physical devices we usually attempt to fix it by unplugging, toggling "android debug mode" on the device and reconnecting.
Make sure your working on an ADMIN ACCOUNT. This problem also frustrated me, but when I switched over to an admin account (on Windows Vista), the adb seemed to correctly install the apk on the device.