Problems with GetProcAddress

I am writing a program to monitor WM_NOTIFY messages in an application so that I can be alerted to updates in the data being displayed. I am currently having problems with my code to write my native DLL to the remote process.

I have the following for my P/Invoke section:

/// <summary>
/// The GetModuleHandleEx function retrieves a module handle for the specified module if the file has been mapped into the address space of the calling process.
/// </summary>
/// <param name="dwFlags">This parameter can be one or more of the following values.</param>
/// <param name="lpModuleName">Pointer to a null-terminated string that contains the name of the module (either a .dll or .exe file), or a pointer to an address in the module (if dwFlags is GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS).</param>
/// <param name="phModule">Handle to the specified module.</param>
/// <returns>
/// If the function succeeds, the return value is nonzero.
/// If the function fails, the return value is zero.
/// </returns>
[DllImport("Kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true, ThrowOnUnmappableChar = true)]
public static extern bool GetModuleHandleEx(UInt32 dwFlags,string lpModuleName,out IntPtr phModule);

/// <summary>
/// The GetProcAddress function retrieves the address of an exported function or variable from the specified dynamic-link library (DLL).
/// </summary>
/// <param name="hModule">Handle to the DLL module that contains the function or variable.</param>
/// <param name="lpProcName">Pointer to a null-terminated string that specifies the function or variable name, or the function's ordinal value.</param>
/// <returns>If the function succeeds, the return value is the address of the exported function or variable.</returns>
[DllImport("Kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true, ThrowOnUnmappableChar = true)]
public static extern IntPtr GetProcAddress(IntPtr hModule, string lpProcName);

My code for using this is as follows: