title: Amazon s3 error on fineuploader version 4.0.3
body: <p>One of our clients is getting this error message when uploading files to our s3 bucket - "Problem asking Amazon to combine the parts!". We can take the same files and upload them OK on our end. Is there any way to capture more info to see exactly why the parts cannot be combined on Amazon's end? We're using the onError callback now and posting it to a log. Is there any way else to dig in deeper?</p>