Twhirl says limit exceeded when it clearly has not been.

I haven't been able to use twhirl for two days. Every time I start it up it says "limit exceeded, paused 5 minutes". I understand that that twitter have a 70 request per hour limit, what troubles me is that my laptop is switched off at night, and when i start it up in the morning and launch twhirl it immediately gives me that error. I've switched back to using twitterific which works fine.