Unfortunately, banning users from individual forums is not currently possible without some form of code hack.
You might check
https://www.ubbdev.com to see if anyone has written such a hack. However, keep in mind that Infopop cannot support hacked boards.
Graeme
Moderator: UBB6 How Do I?
NOTE: Any email requests for support will be ignored."The ships hung in the sky in much the same way that bricks don't." --Douglas Adams