Oracle NT 4 EE sp6a.
I have setup Oracle on my worstation and create a database:
DB name = db1, SID = db1.

When I launch the program "svrmgr30" from the command prompt I receive the following error:
0RA-12203: TNS:unable to connect to destination.
But then if I try the connection from svrmgr30 (connect internal/password@db1) I can connect to my database.
1) Why do I receive this error?

2) Is it necessary to create a new service with Oracle Net8 Assistant in order to connect to my database?

3) When I try to connect thru OEM I cannot see the name of the database, what shoul I do in order to see my database with Enterprise manager?

Any help is really appreciates.
Thank you very much.