Fixes issue4653 - Correctly specify the buffer size to FormatMessageW and
correctly check for errors on two CreateFileMapping calls.
diff --git a/Python/dynload_win.c b/Python/dynload_win.c
index 25b6680..edb6038 100644
--- a/Python/dynload_win.c
+++ b/Python/dynload_win.c
@@ -235,7 +235,7 @@
                            SUBLANG_DEFAULT),
                            /* Default language */
                 theInfo, /* the buffer */
-                sizeof(theInfo), /* the buffer size */
+                sizeof(theInfo) / sizeof(wchar_t), /* size in wchars */
                 NULL); /* no additional format args. */
 
             /* Problem: could not get the error message.