WinXP: What permission needed for Process.WaitForExit()?

[Bert Hyman]

XP Pro SP3

I wrote a short C# app to allow my backup to wait for another program to
finish before proceeding. It boils down to basically

using System.Diagnostics;
Process[] av = Process.GetProcessesByName("avscan");
av[0].WaitForExit();

Unfortunately, this appears to require permission even beyond being a
member of the "Power User" group.

So rather than add the user that does backups to the Administrators group,
is there a specific permission that I can add to that user so that it can
use these functions?

I've seen references to "Performance Monitor Users," but that doesn't exist
on my XP Pro SP3 system.