My first inclination is to assume that a lens error is the problem that is causing the shutdown, but first, there is one more likely possibility, lack of sufficient power. Remove the batteries, check the pins or connectors in the battery compartment, and make sure that they are positioned correctly to contact the battery. Then use a q-tip with alcohol to clean and dry them.
It is also a known issue that digital cameras circuitry can also become much more sensitive to the lower power level produced, so if you have been using the same rechargeable batteries for the life of the camera (more than 4-5 years), then the power capacity of the battery may not be high enough anymore to handle the increased load. A new battery may be the answer.
Having taken out the battery and memory card for over 15 minutes and replaced them I was able to close down the zoom of the camera completely, so it will open, zoom and close on it's own power. Unfortunately having opened it for a second time I still have the Focus error come up on the screen (initially with the hand emblem and warning tones) and although the zoom will operate it will not take photographs and when I go to close the camera down it will only retract the outer most zoom part and not go back into the camera housing (although it did earlier). I have tried operating the camera in it's cradle with power supplied but it makes no difference. The zoom part of the camera appears square and even and firmly in place and I have cleaned as much as possible but I am still unable to take photographs due to the focus error.