I have installed Oracle9i version 18.104.22.168.0 on Windows 2000 server SP4. All is (was) OK. I had to reboot the machine, but when I tried to connect to the database (both using Oracle Enterprise Manager and SQL*Plus tools) I got the errors:
I used the proposed solution adding a shared_servers=0 parameter to a file named init.ora.6222004172117 (the only init.ora I've found), ended the database and restarted it again. It worked okay, but when I reboot the server the problem reappears, and the shared_servers parameter is alredy set. Also I renamed the init.ora.6222004172117 as init.ora, but nothing happens.
You need to find your init.ora file. It is specified in a registry setting under HKLM\software\oracle in a key named something like ora_SID_pfile. That will show you where the "real" init.ora file is. If you're using 9.2.0, you may be using an spfile and if so, then you'll have to make the change using ALTER SYSTEM instead.