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-- (deprecated) Microsoft Windows OS (XP/NT/Vista)
---- 550 "Unknown User"
kaled - 10:46 am on Feb 9, 2010 (gmt 0)Thread source:: http://www.webmasterworld.com/microsoft_windows_os/4074943.htm
In the case of the "Unknown User" error, did you check the header as you did previously? If it's blank again that would be interesting.
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