Microsoft OLE DB Provider for ODBC Drivers error '80004005'
[Microsoft][ODBC Driver Manager] data source name not found and default driver not specified (sound like this in english)

Microsoft OLE DB Provider for ODBC Drivers error '80004005'
[Microsoft][ODBC Driver Manager] Specified driver could not be loaded due to system error 126

Microsoft OLE DB Provider for ODBC Drivers error '80004005'
[Microsoft][ODBC Driver Manager] Specified driver could not be loaded due to system error 5

This are the errors.

I try connecting to an Oracle db using SQLNet shipping with Oracle7.3
and its drivers (I tryed ver 1.0, ver 2.0 and ver 2.5 and none works)
SQLNet is installed on a PDC Win2000 srv and Active Directory and IIS5 as web srv.
The oracle utility ODBCTest run well and the connection is done but when i try to use the same dsn via web asp page the error occurs.
I tryed also to grant permissions to iusr_... (anonymous internet user)
to the file sqo32_73.dll and to all its directory (I hoped the cause was something regarding that) but not works anyway!
The three different errors derived cause I grant and then revoke the permissions decribed above (on a machine that is not a PDC returns system error 5 on a PDC returns system error 126)

On another machine win2000 srv with IIS5 it works well but it isn't a PDC and haven't Active Directory installed.

I'm becoming crazy solving it, thanks to Microsoft, Oracle and my ignorance of course! ;-)