Множественная загрузка. URLLoader и SecurityError #2176

[i.o.]

It could be possible that contentType does not refer to what data you send, but to what data you receive. Try to set the requestHeaders, that should work:

urlRequest.requestHeaders.push(new URLRequestHeader('Content-type', 'multipart/form-data'));

Другими словам, не трогайте _request.contentType