I've had trouble with uploading to AMAZON S3 in SYDNEY with new installs and NEWLY CREATED BUCKETS, the problem appears to be that Amazon takes a while to replicate the bucket names.
On leaving things until the next day, it works.
Simple way to test if you use Sydney, create a test bucket (or use a bucket that you have that is a few days old) and upload to that. In my case, the upload to the old bucket works. The next day, simply rename to your new bucket.