That's actually called godmodding. You can't control others people's characters. But no, you didn't do anything majorly wrong... this Rp is just kind of at its last of its life.
Interest just died down with the players and some just dropped the RP. It is a common enough ocurrance, so don't think it is your fault. It just wasn't the time for this RP.
In any case, I hope you get into more RP's and get even more experience.