Another person had the similar login problem to the one you describe. I am not too sure why! I suspect it has something to do with expiring cookies! Damn cookie monsters. Let me up the expiration time, 30 min does really suck to be honest!

Thanks for making this post btw Celest!
As for the password. I know its a hassle. You only need it once when you register and it is meant to keep out the Hibs and Albs!
EDIT : I increased the expiration time. If that doesn't solve the problem can you please email me exactly what is happening, your time zone, your os etc etc... msinosic@bigpond.net.au cc sinosich@ali.com.au