When I tried logging into data mover after creating a shell database in Windows OS, below error popped up. Also once I have experienced the same error in log file while booting up the application server domain.
PeopleSoft has been making the move from a 32bit application to a 64bit application and it would be working everywhere in 64bit mode, except for in windows. So if you encounter this error, make sure that the 32-bit libraries are installed and are being referred to for the client. Install 32 bit Oracle client, provide listener configuration information in it and add the 32-bit bin path in pointing to 'Add to PATH' parameter in psappsrv.cfg and try to login. Your issue will be resolved. Also ensure the DBBIN parameter in psprcsrv.cfg points to 32-bit Oracle bin path.