HI Calvin,
I hope you have already given the Select privileges to your user:
GRANT SELECT ON SCHEMA <YourSchema> TO _SYS_REPO WITH GRANT OPTION
GRANT EXECUTE ON SCHEMA <YourSchema> TO _SYS_REPO WITH GRANT OPTION
TO use Decision tables, also assign the update privilege to your user:
GRANT UPDATE ON SCHEMA <YourSchema> TO _SYS_REPO WITH GRANT OPTION
Regards,
Vivek