Unreliable Disconnect

Hello Guys,

I am using Task Scheduler to disconnect my PC from the Internet when I am
away from my desk by using it to execute a batch file "rundll32
iedkcs32.dll,CloseRASConnections".

This works 95% of the time but occasionally it fails and Windows reports, in
a white window, that it cannot run properly in a window.

This happens with other msdos launched games too and when it does, it tends
to lock up the system and a normal shut-down is not possible.

Is there any way I can modify the batch file to overcome the problem, or, is
there a freeware application which would do the job right every time?

Thanks already,

Steve