SQL & PL/SQL

Hi,
I am having a problem with PIVOT in Oracle.
I have a view in an oracle 11g database
that returns me data in the format:- (... indicates left out text)

DefinitionID ... AttributeValue FieldID
============ ============== =======
... 3000 X30a9...
... JohnN X4674...

I am then trying to use a PIVOT statement to hopefully give me data
in the format

COLUMN1 COLUMN2
======= =======
JohnN 3000

The PIVOT statement I am trying is

SELECT X4674... AS Column1,
X30A9... AS COLUMN2
FROM (SELECT instanceid, definitionid, attributevalue, FIELDID
FROM PI_ENTITY_INSTANCE_VIEW) up PIVOT (MAX(ATTRIBUTEVALUE)
FOR FIELDID IN (X4674...,X30A9... ) )
where definitionid = hextoraw('7353C67A56C74B5A8234CD16064399E8')

I have used a very similar VIEW and PIVOT statement for sql server
(with necessary changes for Oracle applied) and the
data returns in SQL Server as expected.

Unfortunately I am getting the Oracle error
ORA-56901: non-constant expression is not allowed for pivot|unpivot values

Is there anyway to get a PIVOT working on Oracle where I use the
fieldid's like I do above or is there some other way to supply the vales to the
IN clause to overcome this error?

Thank you for any help you can provide
John Nugent