I am using the PHP class described in this other question, and most of the time it works beautifully.
But then occasionally I get either this:
user warning: S3::putObject():  select/poll returned error
user warning: S3::putObject(): [RequestTimeout] Your socket connection to the server was not read from or written to within the timeout period. Idle connections will be closed.
Before I was using a different class that relied on PEAR and some other services to interact with S3, and I got the [Request Timeout] error nearly every time.