Hi,
Have you experienced this "ORA-01466" issue directly after upgrade? This issue may no longer occur after a certain amount of time, but you can also use the workaround described in the suggested SAP Note 1498109. The cause is also described in the note.
Regarding the "invalid username/password" issue, you can also refer to the SAP KBA 1576837 - "ORA-01017: invalid username/password". What is your kernel version? Are you using SSFS?
Regards,
Bíborka