we can run the following on some instances but not on others, using sqlplus. We have similar problems on both Solaris and WIN2K platforms.
(Note: some instance are on the same server, some will work ok, others won't.)

--Works as expected on an instance
select sys.XMLType.createXML('<AccountAddressStreet1>Smif f St</AccountAddressStreet1>').extract('/AccountAddressStreet1/text()').getStringVal()
from dual;

Smiff St


--Throws an exception on other instance...
select sys.XMLType.createXML('<AccountAddressStreet1>Smif f St</AccountAddressStreet1>').extract('/AccountAddressStreet1/text()').getStringVal()
from dual;

select sys.XMLType.createXML('<AccountAddressStreet1>Smif f St</AccountAddressStreet1>').extract('/
*
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error
ORA-06512: at line 1

We are fairly new to XML, so hopefully this is something basic.
Do we need a certain Oracle patch level (e.g. 903/904) for XML core functionality to work properly?
Any obvious database settings/parameters that are relevant? The init.ora settings are practically the same.
Any special roles or privileges?
Any scripts or prerequisites we may have ommitted from some of the instances?
Any other ideas?