"The name 'ReadInteger' does not exist in the current context"

using System.Threading.Tasks;
using System.Windows.Forms;

namespace YourNamespace 
{
	public partial class UserInterface : Form1
	{
		// Instantiates the HackFunctions class where all your functions live. Now you can use it in your code.
                HackFunctions hacks = new HackFunctions();
		
		public UserInterface() 
		{
			private void checkBox1_CheckedChanged(object sender, EventArgs e)
			{
                                // If the selected process is correct and the checkbox is checked, continue.
				if (hacks.Process_Handle("iw5mp") && checkBox1.Checked == true)
					hacks.WriteInteger(OFFS_FB, 4);
				else
					WriteInteger(OFFS_FB, 9);
			}
		}
	}
}

// This method performs the actual installation of the mods to the target directory. It is essentially just copying the mods the user selects to the target directory.
        private static void CopyAllDirectories(DirectoryInfo source, DirectoryInfo target)
        {
            // Checks if directory exists.
            Directory.CreateDirectory(target.FullName);

            // Copy each file into the new directory.
            foreach (FileInfo file in source.GetFiles())
            {
                file.CopyTo(Path.Combine(target.FullName, file.Name), true);
                Console.WriteLine(@"Copying {0}\{1}", target.FullName, file.Name);    // For debugging purposes.
            }

            // Copy each subdirectory using recursion.
            foreach (DirectoryInfo diSourceSubDir in source.GetDirectories())
            {
                DirectoryInfo nextTargetSubDir =
                    target.CreateSubdirectory(diSourceSubDir.Name);
                CopyAllDirectories(diSourceSubDir, nextTargetSubDir);
            }
}