Many databases on one NT box

Hi,

I am trying to run several small Oracle databases on a single NT machine. They run fine from the command prompt but I would like to use the OEM tools without having to keep changing ORACLE_SID in the registry. I thought that the easiest thing to do would be to configure Net8 services for each of the databases. However, regardless of whether I use a single listener with many database services or one listener per instance, I get "ORA-12505 TNS: listener could not resolve SID given in connect descriptor" for all but the first instance I set up (which connects okay). The other databases appear in the tnsnames.ora and listener.ora files on the server.

Which is the correct approach (multiple databases per listener, or multiple listeners - one per database), and how might I get round this error?

Alternatively, is there any other way to access different databases through the graphical tools without having to modify the registry?

Any help would be very much appreciated,

Thanks

• Bill.