HELP needed with ontape on NT

I have a problem scheduling an ontape archive with the at command on an NT V3.51 installation of Informix OnLine Dynamic Server V7.12 TC2. I have created a bat file with a in-redirected input file containig the responses to the ontape questions and output redirection to log files. When executing this bat file from the command prompt it works fine but when trying to schedule the bat file to run at night it does not work. The reason it does not work is that the executing user "SYSTEM" is not a member of the Informix-Admin group. This user SYSTEM is, as far as I understand, not an ordinary user that can be modified or anything. I have tried to create an ordinary user SYSTEM, included in the proper group but it did not help. I have also tried to grant permission to the group Informix-Admin to alow it to log on in batch. That did not help either. Being brought up with UNIX, NT is sometimes a bit strange!! Regards, Dan Michaeli Tetra Pak Data Systems Lund, Sweden