Is this a traditional logon script or a GPO Startup Script?
I can't remember exactly what is about @priv, but I know I remember that it doesn't work as advertised any more. If I remember correctly @priv is a carry over from Win9x days.
It's a traditional logon script. How can it be a carry over from win9x? Administrators didn't exist in 9x.
I modified the script, but it's the same difference. The sid "S-1-5-32-544" is the SID for the local administrators group. So sidtoname('S-1-5-32-544') == "Administrators" and therefor '@wksta\'+sidtoname('S-1-5-32-544') == @WKSTA + "\Administrators." Regardless though, I did try it the first way first and later changed it to my way thinking something was going on the with sidtoname function.