For the example code you've shown, besides fixing the variable name, you want the fancyLogAdmin.
Also, make sure you're defining CATEGORY_NAME in your command object setup somewhere else in your file or you can change it at that spot.
fancLogAdmin allows for a "optional" 2nd parameter, a boolean, that if not present, defaults to false.
ulx.fancyLogAdmin( calling_ply, true, "#A tested a command on #T", target_ply )
would HIDE from players (except admins with see echo access)
ulx.fancyLog( calling_ply, "#A tested a command on #T", target_ply )
would not hide from players
Error's your getting would be helpful to us in helping you.