unfortunately, Microsoft has added a clever new
   "feature" to Internet Explorer. If the text of
   an error's message is "too small", specifically
   less than 512 bytes, Internet Explorer returns
    its own error message. You can turn that off,
   but it's pretty tricky to find switch called
   "smart error messages". That means, of course,
   that short error messages are censored by default.
   IIS always returns error messages that are long
    enough to make Internet Explorer happy. The
   workaround is pretty simple: pad the error
   message with a big comment like this to push it
   over the five hundred and twelve bytes minimum.
   Of course, that's exactly what you're reading
   right now.