Timed logoff of remote XP PC

I am wanting to automatically log off a remote Windows XP user at a regular time each night (he forgets constantly to do it himself). I’ve created the following batch file, and scheduled it to run at the appropriate time each evening, but no matter what I do, the delay time is NOT recognized. As soon as the schedule task is invoked, the logoff process begins immediately with no delay. I’d like the logoff warn to appear on the user’s screen for 5 minutes just in case anyone is using the PC when the task gets triggered, but like I said, the PC just logs off right away.

Here’s the batch file that I’ve created:

REM ***This batch file is to auto-logoff this PC @ 8:00 PM each night***
@echo off
shutdown -l -f -t 300 -C “8:00 PM LOGOFF”
pause

Any suggestions?