diff --git a/subprocess/NativeMethods.cs b/subprocess/NativeMethods.cs
index 8773cc67..d11e512b 100644
--- a/subprocess/NativeMethods.cs
+++ b/subprocess/NativeMethods.cs
@@ -6,7 +6,7 @@ static class NativeMethods{
         public static readonly IntPtr HWND_BROADCAST = new IntPtr(0xFFFF);
         
         [DllImport("user32.dll")]
-        public static extern bool PostMessage(IntPtr hWnd, uint msg, int wParam, int lParam);
+        public static extern bool PostMessage(IntPtr hWnd, uint msg, UIntPtr wParam, IntPtr lParam);
 
         [DllImport("user32.dll")]
         public static extern uint RegisterWindowMessage(string messageName);
diff --git a/subprocess/Program.cs b/subprocess/Program.cs
index c6ab9baf..0fda1108 100644
--- a/subprocess/Program.cs
+++ b/subprocess/Program.cs
@@ -26,7 +26,7 @@ public override void OnBrowserCreated(CefBrowserWrapper wrapper){
                 base.OnBrowserCreated(wrapper);
                 
                 using(Process me = Process.GetCurrentProcess()){
-                    NativeMethods.PostMessage(NativeMethods.HWND_BROADCAST, NativeMethods.RegisterWindowMessage("TweetDuckSubProcess"), me.Id, wrapper.BrowserId);
+                    NativeMethods.PostMessage(NativeMethods.HWND_BROADCAST, NativeMethods.RegisterWindowMessage("TweetDuckSubProcess"), new UIntPtr((uint)me.Id), new IntPtr(wrapper.BrowserId));
                 }
             }
         }