Oracle 9i Installation problems

I'm having troubling problems with a new installation of oracle. I've tried installing several times but I always get the same problem. During the installation of oracle 9i I get successfully through the entire process untill I get to the database configuration assistant. Each time I get this in the Details screen :
java.lang.ArrayIndexOutOfBoundsException
at oracle.sysman.assistants.dbca.backend.Verifier.calculateCloneDatafilePathsAndSizes(Compiled Code)
at oracle.sysman.assistants.dbca.backend.Verifier.validateFiles(Compiled Code)
at oracle.sysman.assistants.dbca.backend.Host.validate(Host.java:3757)
at oracle.sysman.assistants.dbca.ui.ProgressOnlyHost.performOperation(ProgressOnlyHost.java:115)
at oracle.sysman.assistants.dbca.backend.Host.startOperation(Compiled Code)
at oracle.sysman.assistants.dbca.Dbca.execute(Dbca.java:94)
at oracle.sysman.assistants.dbca.Dbca.main(Dbca.java:143)


I'm not sure what's causing it but I skip it and keep going to finish the installation. When it's finished I try to run sql*plus and I get the error "TNS:Protocol Adapter Error" or "TNS:Service name not specified" depending on whether I enter anything in the host string box. I am a newbie, in fact I'm in an Oracle SQL class right now and I need the default database to practice with because the book assumes I do. The database I'm speaking of is the one with the l/p Scott/Tiger which I'm told is one everyone is familiar with. Unfortuneatly my teacher is not so good with the english so it makes it hard to understand when he tries to explain what I should do so I'm hoping someone here can help. In case it's needed, I'm running a 2.4 Intel w/256mb of ram and WinXP Pro. Thanks for your help in advance.

First check, your database service is up and running, type the following command on command prompt (for example you have installed oracle in D drive of your computer and your service name is ORCL.world , database name is ORCL)

following command show you the all started servcies in your computer:
D:/>net start

try to find out a service look like OracleServiceORCL, if you dont find it then start by typing following command:

D:/>net start OracleServiceORCL

now check again to make sure that service has been started or not.

now create a connection to connect client with your database server (no matter you installed oracle into standalone) using Oracle Net.

Did you create the database when you installed the Oracle?

No, the databases is not installed, I have to skip that during the initial installation in order to finish. I don't know how to install that sample database, any help or a walkthrough using the database configuration assistant or doing it by hand would greatly help.

plz visit
http://download-west.oracle.com/doc.../a95491/toc.htm

web site and go through the database creation process using DCA (database configuration assistant) provided by the Oracle corp..

wait a minute.....Oracle corp. required free registration in term of using this documnt.