diff --git a/rdr/Exception.cxx b/rdr/Exception.cxx
new file mode 100644
index 0000000..5f7799f
--- /dev/null
+++ b/rdr/Exception.cxx
@@ -0,0 +1,64 @@
+/* Copyright (C) 2002-2003 RealVNC Ltd.  All Rights Reserved.
+ *    
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ * USA.
+ */
+#include <rdr/Exception.h>
+#ifdef _WIN32
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <winsock2.h>
+#endif
+
+using namespace rdr;
+
+SystemException::SystemException(const char* s, int err_)
+  : Exception(s, "rdr::SystemException"), err(err_)
+{
+  strncat(str_, ": ", len-1-strlen(str_));
+#ifdef _WIN32
+  // Windows error messages are crap, so use unix ones for common errors.
+  const char* msg = 0;
+  switch (err) {
+  case WSAECONNREFUSED: msg = "Connection refused";       break;
+  case WSAETIMEDOUT:    msg = "Connection timed out";     break;
+  case WSAECONNRESET:   msg = "Connection reset by peer"; break;
+  case WSAECONNABORTED: msg = "Connection aborted";       break;
+  }
+  if (msg) {
+    strncat(str_, msg, len-1-strlen(str_));
+  } else {
+#ifdef UNICODE
+    WCHAR* tmsg = new WCHAR[len-strlen(str_)];
+    FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+                  0, err, 0, tmsg, len-1-strlen(str_), 0);
+    WideCharToMultiByte(CP_ACP, 0, tmsg, wcslen(tmsg)+1,
+		              str_+strlen(str_), len-strlen(str_), 0, 0);
+    delete [] tmsg;
+#else
+    FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+                  0, err, 0, str_+strlen(str_), len-1-strlen(str_), 0);
+#endif
+  }
+    
+#else
+  strncat(str_, strerror(err), len-1-strlen(str_));
+#endif
+  strncat(str_, " (", len-1-strlen(str_));
+  char buf[20];
+  sprintf(buf,"%d",err);
+  strncat(str_, buf, len-1-strlen(str_));
+  strncat(str_, ")", len-1-strlen(str_));
+}