There are so many reasons why this might not be working.
1. The addon doesn't check for ULX permissions, just the group. In that case either it's only granted to admin or maybe you misspelled superadmin. Set superadmin to inherit from admin, that might fix it.
2. The addon has some other way of granting permission to those commands, and it doesn't go by GMod rank.
3...infinity. Numerous other reasons as to why the command isn't working.
What addon are these commands from? Maybe check with the creator. They use a slash so I assume they're from DarkRP or from an addon made for DarkRP. Could be some conflict with FAdmin in that case, idk but it sounds like FAdmin and ULX often get into cat fights.