Hi, according to the manufacturer it could be due to the camera being dropped OR if it is in a bag then the bag was dropped or crushed. You can check on this more on their website:
[http://|http://support.casio.com/answer.php?rgn=4&cid=001015047008&qid=45570&num=1]
IF the device has the anti shock/ anti shake feature and the camera was dropped (even if it did not seem to be a bad drop) the sensor for that feature could have been jarred badly enough to cause that message to appear.