Logon script and WinShield help

Need help with logon script in our NT4 environment. I’ve wrote a simple script to install and configure VNC remote access software on workstations when a user logs on. The problem is that some of our Win98 workstations have WinShield installed on them.(This is an elementary school environment. We installed that to keep kids from changing settings, screensavers, etc.) We have set WinShield to disable DOS, but in doing so, this prevents my script from executing the install of VNC. Does anyone know what commands I need in my script to get around this? I suppose it would have to disable WinShield, execute the install, then re-enable WinShield. Any suggestions are appreciated.