you are not specified what the error got at the time on import...

try this....

You will have to run the structural export with CONSTRAINTS=Y and the data export with CONSTRAINTS=N. Follow these steps:

Run the first export with parameter ROWS=N and parameter CONSTRAINTS=Y.
Run the second export with ROWS=Y and CONSTRAINTS=N.
Run the first import to build the tables with constraints.
Disable all foreign key constraints using ALTER TABLE DISABLE CONSTRAINT
.

5. Run the second import that imports data without building constraints.

6. Enable all foreign key constraints using ALTER TABLE ENABLE CONSTRAINT .