Web Player crashes during WWW request to server

I understand that this topic comes up a lot, but my question is about the Web Player crashing when my game requests data from Amazon S3 via the WWW class.

I do not see this issue within the editor, but deploying my WebPlayer, on Google App Engine, and then reaching the point where I GET from S3 causes the webplayer to crash.

The Error log left by the webplayer says the following:

WWW Error: Error when creating request. GET request with custom headers is not supported. for URL: https://my-storage.s3.amazonaws.com/myDir/myFile.json

When I use a similar request to a public directory on Dropbox, there is no crash, but the request also fails.

WWW Error: Failed downloading dl.dropboxusercontent.com/u/7782207/spare-change/weapons/0.json for URL: dl.dropboxusercontent.com/u/7782207/spare-change/weapons/0.json

Try it for yourself: http://webroleplay.appspot.com

username: test1

password: t