Amazon S3 Getting 501 Error on PUT

Question

In testing a new app one tester always has his uploads to S3 fail. We're sending a PUT request of a ~1.2mb file to S3 and setting it's ACL perms. For him, he always gets a 501 - Not Implemented error.

Here are his headers on the request:

"Accept-Encoding" = gzip; 
Authorization = "AWS ###:###";
"Content-Encoding" = gzip;
"Content-Length" = 1420267;
"Content-Type" = "application/octet-stream";
Date = "Thu, 6 Oct 2011 02:59:47 +0000";
"User-Agent" = "MyApp 1.0 (iPhone; iPhone OS 4.3.1; en_US)";
"x-amz-acl" = "public-read-write";

Here are the response headers:

Connection = close;
"Content-Length" = 321;
"Content-Type" = "application/xml";
Date = "Thu, 06 Oct 2011 03:00:14 GMT";
Server = AmazonS3;

Any thoughts are welcome!

Response comes back with status code 501 and string - "A header you provided implies functionality that is not implemented"

Answer 1

501 response code from Amazon may be sent if no Content-Length is supplied.

Since you are saying that you do, I suggest running the request through a proxy ( Charles for Mac or Fiddler for Windows) and making sure that the request that's being sent actually includes the Content-Length header