Why not (OID) in JDeveloper10g?

Hello!,
Using JDeveloper10g (ORACLE) I can connect to PostgreSQL database
on local machine;
BUT! when trying to open informations on table structure, I receive this ERROR
MESSAGE
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See image attached!

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and I'can't access table structure informations (I.E. ftable.fields list)!

This is what says Oracle about this same error on his help on line into
JDeveloper10g.
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Cause: A database failure occurred while trying to generate an object ID (OID)
and object reference (REF). When a new row is created on an entity which maps
to an Oracle object table, an OID and REF for the new row are generated. This
executes a SQL statement like select a.oid, make_ref(, a.oid) ... Somehow,
this statement is failing. Action: Check the following: Are you using the
right version of Oracle database? Is the table in question an object table?
This error normally carries a detail exception from the database, which will
give further information about the database failure. Take a look at the
detail exception and address the database problem.
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Do anyone knows why this happen?, is it possible to correct already the
problem?, or anyone does encountered the same problem?
--
Roberto Della Grotta