string parameter in Crystal 9 command against Oracle getting ORA-24374

[Mountaine]

This command works fine:
SELECT INSTR('2000,2700',SUBSTR(fieldname,1,4)) TESTFIELD FROM tablename

but when I create a parameter MyParam within the command and give it a default value of 2000,2700 I get an ORA-24374 with this:

SELECT INSTR({?MyParam},SUBSTR(fieldname,1,4)) TESTFIELD
FROM tablename

And I still get the ORA-24374 with this:

SELECT INSTR('{?MyParam}',SUBSTR(fieldname,1,4)) TESTFIELD
FROM tablename

 

[Mountaine]

In case anyone cares, the problem was solved when I switched from Oracle's driver to the CR driver for Oracle.