Index: src/runtime/misc.m
==================================================================
--- src/runtime/misc.m
+++ src/runtime/misc.m
@@ -21,10 +21,14 @@
 #include <stdio.h>
 #include <stdlib.h>
 
 #include "ObjFWRT.h"
 #include "private.h"
+
+#ifdef OF_WINDOWS
+# include <windows.h>
+#endif
 
 #ifdef OF_AMIGAOS
 # define USE_INLINE_STDARG
 # include <proto/exec.h>
 # include <clib/debug_protos.h>
@@ -53,26 +57,38 @@
 }
 
 void
 objc_error(const char *title, const char *format, ...)
 {
-#ifdef OF_AMIGAOS
+#if defined(OF_WINDOWS) || defined(OF_AMIGAOS)
 # define BUF_LEN 512
 	char message[BUF_LEN];
 	int status;
 	va_list args;
-	struct Library *IntuitionBase;
-# ifdef OF_AMIGAOS4
-	struct IntuitionIFace *IIntuition;
-# endif
-	struct EasyStruct easy;
 
 	va_start(args, format);
 	status = vsnprintf(message, BUF_LEN, format, args);
 	if (status <= 0 || status >= BUF_LEN)
 		message[0] = '\0';
 	va_end(args);
+# undef BUF_LEN
+#endif
+
+#if defined(OF_WINDOWS)
+	fprintf(stderr, "[%s] %s\n", title, message);
+	fflush(stderr);
+
+	MessageBoxA(NULL, message, title,
+	    MB_OK | MB_SYSTEMMODAL | MB_ICONERROR);
+
+	exit(EXIT_FAILURE);
+#elif defined(OF_AMIGAOS)
+	struct Library *IntuitionBase;
+# ifdef OF_AMIGAOS4
+	struct IntuitionIFace *IIntuition;
+# endif
+	struct EasyStruct easy;
 
 # ifndef OF_AMIGAOS4
 	kprintf("[%s] %s\n", title, message);
 # endif
 
@@ -98,11 +114,10 @@
 # endif
 
 	CloseLibrary(IntuitionBase);
 
 	exit(EXIT_FAILURE);
-# undef BUF_LEN
 #else
 	va_list args;
 
 	va_start(args, format);