C#

RegistryKey
regKey = Registry.LocalMachine
regkey = regKey.OpenSubKey("Software");
regkey = regKey.OpenSubKey("Adobe");
regKey = regKey.OpenSubKey("Adobe Reader"); /* this line returns a null exception, if this line is commented out I get the expected results on the Adobe Key */

RegistrySecurity = regKey.GetAccessControl();

string fileName;

public void checkUpdates()
{
	foreach (Uri uri in uriList)
	{
		fileName = uri.AbsolutePath.Remove(0, 1);

		if (!File.Exists(fileName))
		{
			doUpdates(true, uri);
			wasUpdated = true;
			continue;
			//'  There's more in the foreach but I don't think it's relevant
		}
	}
}
public void doUpdates(bool checkUpdates, Uri uri)
{
	WebClient client = new WebClient();
	client.DownloadFileCompleted += new AsyncCompletedEventHandler(client_updateFinished);

	//'  We found updates so download the new files.
	if (checkUpdates)
		client.DownloadFileAsync(uri, fileName);
}

private void client_updateFinished(object sender, AsyncCompletedEventArgs e)
{
	if (File.Exists(fileName))
	{
		//*  Here is where I crash, Error quoted below
		xmlDoc.Load(fileName);
	}
}

MySqlConnection con = new MySqlConnection("SERVER=localhost;" +
     "DATABASE=db;" +
     "UID=user;" +
     "PASSWORD=root;");

 MySqlDataAdapter da = new MySqlDataAdapter("Select * From test", con);
 MySqlCommandBuilder MyCB = new MySqlCommandBuilder(da);
 DataSet ds = new DataSet("test");

 da.MissingSchemaAction = MissingSchemaAction.AddWithKey;
 FileStream fs = new FileStream(@"C:\image.rar", FileMode.OpenOrCreate, FileAccess.Read);

 byte[] MyData = new byte[fs.Length];
 fs.Read(MyData, 0, System.Convert.ToInt32(fs.Length));

 fs.Close();

 da.Fill(ds, "test");

 DataRow myRow;
 myRow = ds.Tables["test"].NewRow();

 myRow["id"] = "12";
 myRow["blobdata"] = MyData;
 ds.Tables["test"].Rows.Add(myRow);
 da.Update(ds, "test");

 con.Close();

MySqlConnection con = new MySqlConnection("SERVER=localhost;" +
    "DATABASE=db;" +
    "UID=user;" +
    "PASSWORD=root;");

MySqlDataAdapter da = new MySqlDataAdapter("Select * From test where id = 12", con);
MySqlCommandBuilder MyCB = new MySqlCommandBuilder(da);
DataSet ds = new DataSet("test");

byte[] MyData;

da.Fill(ds, "test");
DataRow myRow;
myRow = ds.Tables["test"].Rows[0];

MyData = (byte[])myRow["blobdata"];
int ArraySize;
ArraySize = MyData.GetUpperBound(0);

FileStream fs = new FileStream(@"C:\Data\image.rar", FileMode.OpenOrCreate, FileAccess.Write);
fs.Write(MyData, 0, ArraySize);
fs.Close();