Navigate to the following folder: C:\Windows\Repair\.
Find the autoexec.nt file, highlight it, and go to Edit–>Copy. Note that if a different file was referenced in the error message then copy that one instead.
Navigate to C:\Windows\System32 and then go to Edit–>Paste.
If you continue having the problem then please see http://support.microsoft.com/kb/324767 for additiuonal solutions.