Okay, there's been a problem with passwords being created recently.
I'm not sure what caused it (it seemed to happen completey out of the blue) but I've made something so you can fix your password if you recently created an account, verified, and cant login, try the below form.
I put the fix directly into the CreateUser jsp so it should do it on all new accounts.
It's a bit of a hack but I'll have to do for now.