Canon MV800i Cassette won't load! (by 2 users)

My Camcorder was charging as per usual - i went to use it and a message appeared on the screen saying REMOVE CASSETTE! so that what i did. Only prob is that now it won't load any cassettes at all, but if you close the cassette compartment it closes happilly. In the manual it tells you just to unload the original cassette and then re load!! Well this doesn't work!! It is like it doesnt like the cassette but its the same ones I have used for eva - have tried new ones too!!