OK, so maybe we can solve your issue now by replacing 'index.php' by 'Index.php' at line 413. But that does not tell us why this 'I' is capitalized.
Moreover I thought to replace this 'index.php' by $GLOBALS['wp_rewrite']->index but that would not help in your cas as this variable does not contain a capital 'I'.
Is 'index.php' with a capital I in your web.config file? Is your filename 'index.php' with a capital I in your WordPress directory? Could you test with 'PHP_SELF' instead of the 'SCRIPT_NAME' in the debug info?