IE10 - Intranet site - Writing a file to the local file system

Hi,

I am writing an Intranet site and would like to write a blob somewhere on the filesystem.  What is the best way of doing this?  I already have the blob stored in indexeddb.  I was trying this:

						var reader = new FileReader();
						reader.onload = function (file) {
							var stream = new ActiveXObject("ADODB.Stream");
							var r = file.target.result;
							var ary = new Uint8Array(r);
							stream.Type = 1;
							stream.Open();
							try
							{
								stream.Write(ary);
								stream.SaveToFile(tempPath, 1);
								stream.Close();
							}
							catch (ex) {
								stream.Close();
								throw ex;
							}
						};
						reader.readAsArrayBuffer(f);

but the Write throws this exception: "Arguments are of the wrong type, are out of acceptable range, or are in conflict with one another."

Any help would be appreciated.