Identify your SQL Server version and SP

--
--For SQL 6.5 or later
--
select @@version
go
sp_server_info
go

--
--For SQL 2000 or later
--
SELECT SERVERPROPERTY('productversion'), SERVERPROPERTY ('productlevel'), SERVERPROPERTY ('edition')
go

EXP-00056: ORACLE error 904 encountered

Oracle Version: 9.2.0.8.0

Error Messsage when tried to export a schema:

EXP-00056: ORACLE error 904 encountered
ORA-00904: "SYS"."DBMS_EXPORT_EXTENSION"."FUNC_INDEX_DEFAULT": invalid identifier

Explanation from Metalink Note:358508.1:

After the patchset installation, the data dictionary components have not been upgraded to the patchset release (e.g. 10.1.0.4).

A patchset (e.g. 10.1.0.4) was applied to an existing ORACLE_HOME install but one or more of thepatchset steps were not performed per the patchset readme to bring the database components up to the same version as the patched software as shown in DBA_REGISTRY.

If the database components versions do not match the software and the running instance then the exp utility fails as it finds an earlier version of the exp packages in the database.

Check:
From the following I can see three components are still have the old version.
select COMP_ID,COMP_NAME,VERSION,STATUS,SCHEMA,PROCEDURE from DBA_REGISTRY
COMP_ID COMP_NAME VERSION STATUS SCHEMA PROCEDURE
-------- ------------------------------ ---------- ----------- -------- -----------------------------------
CATALOG Oracle9i Catalog Views 9.2.0.6.0 VALID SYS DBMS_REGISTRY_SYS.VALIDATE_CATALOG

CATPROC Oracle9i Packages and Types 9.2.0.6.0 VALID SYS DBMS_REGISTRY_SYS.VALIDATE_CATPROC

OWM Oracle Workspace Manager 9.2.0.1.0 VALID WMSYS OWM_VALIDATE

3 rows selected.

Suggested Solution:
Connect with SYS user with SYSDBA privileges
SQL> STARTUP MIGRATE
SQL> SPOOL patch.log
SQL> @?/rdbms/admin/catpatch.sql
SQL> SPOOL OFF
SQL> SHUTDOWN
SQL> STARTUP