Masking in AS2

This masking code doesn’t work. Why is this? The variables such as test.jpg is saved in the right place and ‘mask’ is labeled for export etc… can anyone help - it should be as easy as pie. In fact it should work the way Ive done it no!?

function maskit()
{
    content_mc.cframe.loadMovie("test.jpg");
    content_mc.attachMovie("mask","mask",1);
    content_mc.mask.setMask(content_mc.cframe);    
}
maskit();

Thanks!:eye: