If you login from a client application, such as OEM, you must setup
the
password file on the server with orapwd to allow SYSDBA or SYSOPER
access.
Steve
There are two things I can think of to check. First you
should connect internally, and grant SYSDBA to the system
user. If you get errors doing that, you may need to create a
password file. The Oracle8 Administrator's Guide has a
chapter explaining password files.
Jonathan