Can you post the macro you were using it for? Maybe there is something then that can give some idea how to make it work. Mine is
/micon "Company Chocobo" mount
/ac "Mount Roulette"
/mount "Company Chocobo"
/ac Sprint
To summon random mount if in mountable area, to mount my chocobo if my companion is out and to use sprint if in city or dungeon (or in fight, in essence unable to summon mount). It works to what I want it to work, but if I'm summoning mount it throws error "already using an item" and if using sprint it says "unable to mount" adding the aforementioned macro error commands in any configuration to it has not been working to remove them.