Storing a binary file with Visual Basic and ADO

I am trying to store a binary file with Visual Basic 6.0 and ADO and I
use the oid data type. The same code with Oracle and the clob type works
but with PostgreSQL I receive an error saying "Multiple Step Operation
generated errors. Check each status value.".
I am using the ODBC drivers and I assign a String to the Oid but it
fails. I have also tried with a bytes array and with variant data type
but the same error happen.
If I use Java and JDBC it works with byte array reading from a stream.
Thank you.