I've got the same problem as Admesser. When the OTA 5.1 update installed (last night, since I hadn't left wireless on for awhile), it killed all screensavers. It is not bricked. I can turn the device on and off, and it works to read, and appears to have full functionality except it just no longer has any kind of screensaver at all. Thanks to reading Admesser's post, I have not tried to uninstall the jailbreak (data.tar.gz method).
Now I've checked the Kindle Touch Hack wiki page and it says the screensaver hack I used (not yifanlu's) apparently does not work with the 5.1 update, but that the work around is to use yifanlu's simple version. So I'll wait until I get home tonight and try downloading that one. (Hopefully the underlying jailbreak is still working.)
Last edited by Portia; 05-30-2012 at 12:38 PM.