I could be wrong, but I think I read something saying that if you get your password wrong five times, you'll be locked out for that day, but you can log in again the next day. If you're sure you haven't got your password wrong, that would suggest someone else has been trying to log into your account, either to try and get access to it or purposely getting it wrong so your account gets locked.
When it says account suspended it just means that the log-in is suspended and not the actual application has been cancelled. For this to happen though someone would need to know your application number and username
Who has access to this information and is a foe of yours?
That happened to me a few times (quite a lot actually, lol), you either have to wait for tomorrow, or you can ring them up and tell them to unlock it (if your applying as an individual), but if your doing it through your school you can just go to your tutor or whoever is coordinating the UCAS Applications (at our school it was the senior tutors), and tell them to unlock your account (they can do it instantly online when they login as staff).
I think the reason this happens is because your web browser tries to auto-complete uour login information and log in for you. ucas does not allow the personal ID number to be auto-completed, hence, an invalid login attempt.