OLEDB connection does not want to work. Help!!

Hi all, I am pulling my hair trying to make work an OLEDB
connection to POSTGRES.

Let me anticipate that, except for the connection string
I am using the same code (VB.NET, Oledb) that has already
proved to work fine with all the following systems:

sqlserver, Mysql, db2, access, Oracle
[to say although I know nothing about Postgres, in general I should
know how to deal with OleDb]

This one is the only one DBMS is giving me headache.
Could you please help me out to spot the problem?

I work now on XP, with VB.NET. I get connected. But, after that,
nothing seems to work.

my connection string looks like:

Me.ConnectionString = "Provider=PostgreSQL.1;Data
Source=MYDATABASE;User ID=postgres;Location=MioDb;Password='mypsw'"

Just at the very first and fundamental instruction:

OleDbConnection.GetOleDbSchemaTable(System.Data.OleDb.OleDbSchemaGuid.Provider_Types,
New Object() {Nothing, Nothing})

or any other one like:

OleDbConnection.GetOleDbSchemaTable(System.Data.OleDb.OleDbSchemaGuid.Tables,
New Object() {Nothing, Nothing, Nothing, Nothing})

I get an error. My error is:

PostgreSQL.1 failed with no error message available, result code:
E_OUTOFMEMORY(0x8007000E)

(Needless to say I have no memory problem my ram and my disk have
several Gigs free)

What do I have to do (before suicidal)?

-tom