diff --git a/bin/silverlight/Moxie.cdn.xap b/bin/silverlight/Moxie.cdn.xap
index ea045c9c..dbfcce12 100644
Binary files a/bin/silverlight/Moxie.cdn.xap and b/bin/silverlight/Moxie.cdn.xap differ
diff --git a/bin/silverlight/Moxie.min.xap b/bin/silverlight/Moxie.min.xap
index ae44ff72..ef60d4fb 100644
Binary files a/bin/silverlight/Moxie.min.xap and b/bin/silverlight/Moxie.min.xap differ
diff --git a/bin/silverlight/Moxie.xap b/bin/silverlight/Moxie.xap
index bfa33e16..3a9f389f 100644
Binary files a/bin/silverlight/Moxie.xap and b/bin/silverlight/Moxie.xap differ
diff --git a/src/silverlight/Com/XMLHttpRequest.cs b/src/silverlight/Com/XMLHttpRequest.cs
index 2d47a675..b57d7b06 100644
--- a/src/silverlight/Com/XMLHttpRequest.cs
+++ b/src/silverlight/Com/XMLHttpRequest.cs
@@ -261,7 +261,7 @@ public void send(ScriptObject args, object blob = null)
 					header +=
 						dashdash + boundary + crlf +
 						"Content-Disposition: form-data; name=\"" + _blobFieldName + "\"; filename=\"" + _blobName + '"' +
-						crlf + "Content-Type: " + _options["mimeType"] + crlf + crlf;
+                        crlf + "Content-Type: " + (!String.IsNullOrEmpty(_options["mimeType"]) ? _options["mimeType"] : "application/octet-stream") + crlf + crlf;
 				}
 
 				_multipartHeader = _stringToByteArray(header);