Code:
using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace MediviaLightHack
{
    publicpartialclassMediviaLightHack : Form
    {
        Process MediviaProcess;
        IntPtr MediviaProcessHandle;
        uint MediviaBaseAddress;

        uint WorldLightAddress;
        uint WorldLightPointer = 0xDE18A;
        uint WorldLightNop1 = 0xDE188;
        uint WorldLightNop2 = 0xCCD23;
        byte[] WorldLightNopArray1 = new byte[6] { 0x90, 0x90, 0x90, 0x90, 0x90, 0x90 };
        byte[] WorldLightNopArray2 = new byte[10] { 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90 };

        uint SelfLightAddress;
        uint SelfLightPointer = 0x54C090;

        System.Timers.Timer LightHackTimer;

        [DllImport("kernel32.dll")]
        static extern IntPtr OpenProcess(uint dwDesiredAccess, int bInheritHandle, uint dwProcessId);

        [DllImport("kernel32.dll")]
        public static extern int ReadProcessMemory(IntPtr hProcess, IntPtr lpBaseAddress, [In, Out] byte[] buffer, uint size, out IntPtr lpNumberOfBytesRead);

        [DllImport("kernel32.dll")]
        static extern int WriteProcessMemory(IntPtr hProcess, IntPtr lpBaseAddress, [In, Out] byte[] buffer, uint size, out IntPtr lpNumberOfBytesWritten);

        public MediviaLightHack()
        {
            InitializeComponent();
        }


        private void MediviaLightHack_Load(object sender, EventArgs e)
        {
            label1.Text = "Looking for Medivia client.";
            foreach (Process process in Process.GetProcesses())
            {
                if (process.MainWindowTitle.Equals("Medivia Online", StringComparison.CurrentCultureIgnoreCase))
                {
                    label1.Text = "Medivia client found.";

                    MediviaProcess = process;
         // use OpenProcess to retrieve and store the handle to the Medivia client for future use with Read/WriteProcessMemory
                    MediviaProcessHandle = OpenProcess(0x1F0FFF, 0, (uint)MediviaProcess.Id);
         // same with the base address
                    MediviaBaseAddress = (uint)MediviaProcess.MainModule.BaseAddress.ToInt32();

                    IntPtr ptrBytesRead;
                    IntPtr bytesWritten;
                    byte[] buffer = new byte[4];
         // read and store the value from the pointer for the world light address
                    ReadProcessMemory(MediviaProcessHandle, new IntPtr(WorldLightPointer + MediviaBaseAddress), buffer, 4, out ptrBytesRead);
                    WorldLightAddress = BitConverter.ToUInt32(buffer, 0);

         // nop (fill with 0x90) the two addresses that alter the world light value
                    WriteProcessMemory(MediviaProcessHandle, new IntPtr(WorldLightNop1), WorldLightNopArray1, 6, out bytesWritten);
                    WriteProcessMemory(MediviaProcessHandle, new IntPtr(WorldLightNop2), WorldLightNopArray2, 6, out bytesWritten);
         // write 250 (max light value) to the world light address
                    WriteProcessMemory(MediviaProcessHandle, new IntPtr(WorldLightAddress), BitConverter.GetBytes(250), 1, out bytesWritten);

         // read and store the value from the pointer for the self light address
                    ReadProcessMemory(MediviaProcessHandle, new IntPtr(SelfLightPointer + MediviaBaseAddress), buffer, 4, out ptrBytesRead);
                    SelfLightAddress = BitConverter.ToUInt32(buffer, 0) + 0xA4;

         // create and start a timer to continuously set the self light address value every 100ms
         // alternately, you could set this value once like the world light address and nop anything that modifies it (I never took the time to find the addresses that does that)
                    LightHackTimer = new System.Timers.Timer(100);
                    LightHackTimer.Elapsed += LightHackTimer_Elapsed;
                    LightHackTimer.Start();
                    label1.Text = "Light hack actively patching.";
                    return;
                }
            }
            label1.Text = "Medivia client not found.";
       }


       private void LightHackTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
       {
      // this will set the self light address to 250 (max light value)
            IntPtr bytesWritten;
            WriteProcessMemory(MediviaProcessHandle, new IntPtr(SelfLightAddress), BitConverter.GetBytes(250), 1, out bytesWritten);
       }
    }
}

does anyone know and want to help me to get this to work?
thanks in advance!