I am getting an ORA-22926 when passing a clob to the REPLACE function in 11gR2. I found this comment from someone else who experienced this:
1. Identified the issue as the replace function that works on Oracle 10gR2, but not on 11g for the CLOB of some
of the xml files for some character setting in the Oracle database.
2. Submitted a service ticket to Oracle.
3. Oracle provided a workaround solution.
4. Implemented the Oracle workaround solution.