The iTunes password prompt is absolutely maddening. If I make multiple purchases in iTunes it refuses to accept my password after the first purchase i.e. I can

The iTunes password prompt is absolutely maddening. If I make multiple purchases in iTunes it refuses to accept my password after the first purchase i.e. I can buy one film, but to buy another I have to restart. Never mind that I check the remember me box whenever I get the chance (which appears to be shown at random in the login box).