I seem to have the same situation too. At first i thought its the setting on my cam, but when i attended the PLUG meeting, i realise that even when i set the same settings as the other FZ20 users and follow every rule in the book my jitter warning still comes on very very often, while the others do not have this problem. And its on a tripod somemore. Exactly the same setting and setup as everybody esle.
zhao5576 i also realise u bought your cam slightly later then mine. Dont know whether they did something to the settings of the jitter sensor, make it more sensitive or whatever.
But i will be going for the outing this sat at panasonic buliding, hopefully the people there can provide some explaination or help.