This is what I did
1. Download Fast Web Installer from the Market
2. Run the Fast Web Installer
3. Reboot phone.
4. Went to Appbrain app within phone and synced apps once rebooted.
5. Clicked home, NOT back, and went to Fast Web Installer app. Enabled it, then clicked HOME, NOT back.
6. Go to this link to download Angry Birds
Angry Birds Lite Beta - Android app on AppBrain
7. On your PC, go to the Appbrain web site, and click on "My Apps" at the top left corner by the search bar.
8. I clicked on "cancel install" on angry birds lite app, then clicked install again.
9. Downloaded PERFECTLY on my Hero!hope this helps