Have been trying to connect to a schema in 11g (v11.2.0.1.0) from a PC with a 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?