Hard to tell for sure since poster cleaned up the original post but, ORA-04091 "Mutating Table Error" happens when a trigger attempts to select from, update or delete on the table that hosts the trigger.
_____________________________________
Pablo (Paul) Berzukov
Author of Understanding Database Administration available at Amazon and other bookstores.
Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.