Can 2 databases on the same machine?

I definitely need advices on multiple database creation on a single machine. My situation is like this:   We have only one server, there are many client machines (PC) connected to the server. The server is running Solaries 2.5.1 OS,  right now we have a running database ( inventory) in oracle account,  when I try to create another database( accounts) in oracle account, I always got an error saying " can't start, the instance is already running ora 01081', it asked me to shutdown frist.But when I statup  again, it only can start one db,the second will not be allowed to start, do you think I can start both databse on the same account  on the same machine?
  Second, I tried to create a database manually in a different account,  with all required files and executables belonging to that account,  the databse did come up, but when I tried to logon on, I always  got a message, saying " DBMS_STANDARD must be created first, ora 6554"  do you have any idea which script I should run to create the  DBMS_STANDARD package ?
   Any advice will be helpful, Thanks in advance.

 Sean Zhang
 <zhang_at_visi.net> Received on Wed Jun 04 1997 - 00:00:00 CDT