[ANDROID JB BUG] Widgets get lost on reboot
There is a known issue with Android JellyBean version (4.1.x) where paid apps get installed on SD card even though they explicitely require to be installed on internal memory.
App with widgets are required to be installed on internal memory to avoid widget malfunction.
If you experience such issue, you can use System Tuner to check the app location and if necessary move it back to internal memory.
Google bug tracker: http://code.google.com/p/android/issues/detail?id=34880