The current (LiveCode 4.6.3, Oct 2011) release of LiveCode for Android development does not accept the revision 3 directory structure of the Android 2.2 (Froyo) SDK and needs some directory structure tweaking as below:
Copy the folder<android-sdk>\platform-tools\
You need to do this when in the Edit menu Preferences dialog for the Mobile Support item, if it fails with an error message saying:
The chosen folder is not a valid Android SDK. Please ensure you have installed it correctly, and enabled support for Android 2.2 (Froyo).