Oracle Database Discussions

Hello. I am taking an introductory Oracle SQL class. The professor gave us a link to install Oracle 10g release 2, which I followed and performed on my Windows 7 64-bit laptop. The installation seemed to run through okay. When asked (again, per instruction), I created a database named CIS276 (the class name) instead of "orcl" as suggested during the setup. I am having problems getting connected to the database, however, and since the class is online, I can't go to our campus to sit down with the professor to work out where the trouble is, so I'm hoping somebody out here can help me. Here's where I am:

I am able to get to the Enterprise Manager through the loopback address and port that was given to me during installation. I am able to log into EM using the SYS account with the password I entered during install. I get to a screen that has a button labelled "Startup/Shutdown." When I click that button, I am taken to a screen asking for Host credentials (OS account name and password) and database credentials (I use "SYS", the password I created, database is already filled in, and "SYSDBA" for "Connect as"). After entering this information, I click on OK. I get an error message at the top of the screen saying: "Couldnot contact the agent. Verify that the url for the agent is null." I looked up this string and a suggestion was to run " lsnrctl status"--I think (I've been trying a lot of things over the past couple of days to try to get this running) and the program replied that the environment variable "ORACLE_SID" wasn't set. I looked up what I was supposed to do and went into Windows 7 Environment area and set the value.

I rebooted the computer and tried again and am still getting the same problem. So I Googled the error message again and saw a suggestion to stop and restart dbconsole. When I did that, I got an error (stopping and starting) telling me that I was denied access.

At this point, I felt I'd better stop and get any suggestions from more experienced Oracle users. If anybody could give me some suggestions as to what to try next, I'd truly appreciate it.

And one other question: when I followed the link to download Oracle, there was another download listed called something like "Companion Disk 2". Is this a necessary download or is it just extra stuff that I may not use for now?

Thank you again.

Eric S. Bauman