Dear if you have Oracle9i Release 2 (9.2.0.1.0) and updated with 9206 patch please run the catpatch.sql from Oracel_Home/rdbms/admin/, as follows

1. Shutdown the database
2. startup the database with Migrate option
SQL > startup migrate
3. Then run the catpatch.sql from with the above said path
SQL> @Oracel_Home/rdbms/admin/catpatch.sql
4. Shutdown the database
5. Start the database normally

You can verify the version before and after the dba_registry

SQL> select comp_id,version from dba_registry;

Now you can run exp utility with out any problems, for more clarification please read readme file of the above said patch

Take care