I have run your batch file and, under Windows 98SE, it fails at the line "shutdown -s %t %" as the programme "shutdown" cannot be found. If you construct your batch file with the first line "@echo off" removed, you will be able to see the error messages that are generated and thus the line containing the problem. All lines of the batch file will be displayed on screen when the file is run so it can be a bit confusing.
If you just want a line that will shutdown Windows try :-
Hope this helps, Peter.