One of the common errors that Amazon S3 users come across is "The difference between the requested time and the current time is too large" or "Your computer clocks are not synchronized". This error often occurs when your computer clock is not synchronized properly. Amazon returns an error code if the request doesn't come in a certain time interval.
We recommend to make sure your computer clock is set properly and http://wwp.greenwichmeantime.com/ can help. After synchronizing computer clock the error is usually gone.