ok.. sorry about that, i started rambling .... 
Ok lets start from the beginning, your users are running personal logon scripts? are these personal login scripts "kix scripts" or "bat files"?
For your win9x computers you should have no problem launching the supredat at logon however you chose to do it.
Your NT users will be broken down in to 2 main groups, those with local admin rights and those without local admin rights. For those with rights you can treat them just like you would the win9x users and launch the superdat from the logon script with out any special requirements. For those with out rights you will need to grant the superdat program local admin rights, this is accomplished with the NT Resource Kit tool SU.exe .
Using SU leads to some problems
1. Getting it installed, you have to have admin rights to install SU, but you need SU to grant a program admin rights, see the catch 22? I wrote a script that is ran from an administrators computer that will install SU onto a list of target computers (that fixes this problem).
2. Using SU requires that you place an administrators username/password into a plain text file that anyone can read. This is an extremely bad breach of security! But some people will think of it as an acceptable risk, the final call is up to you.
I have this same problem here too, and I have taken a different approach to fix it. To see what my solution was go here http://kixtart.org/board/Forum2/HTML/000834.html
Always glad to help
Bryce