I'm trying to connect to a schema on 11g (v11.2.0.1.0) from a PC with 9i (v9.2.0.1) client. It seems to connect fine to some schemas, but not this one - it comes back with a ORA-01017 Invalid Username/Password error every time.
The username and password are DEFINITELY correct - can anyone think of a reason why this wouldn't work?
Are there any fundamental incompatibilities between 9i and 11g?
The user and password are DEFINITELY incorrect. Oracle 11g credentials are case sensitive, so try:
ALTER SYSTEM SET SEC_CASE_SENSITIVE_LOGON = FALSE;
and alter password.
http://oracle-base.com/articles/11g/case-sensitive-passwords-11gr1.php