The issue here isn’t with the schema but rather how tables are being joined in Oracle. From the link in the screenshot:
Cause: A column name used in a join was defined in more than one table and was referenced ambiguously. In a join, any column name that occurs in more than one of the tables must be prefixed by its table name or table alias when referenced.
Action: To avoid ambiguity, prefix references to column names that exist in multiple tables with either the table name or a table alias and a period. For example, if tables EMP and DEPT are being joined and both contain the column DEPTNO, then all references to DEPTNO should be prefixed with the table name, as in EMP.DEPTNO or DEPT.DEPTNO.
You may need help from a DBA on this one