You stated ' It is like the user does not have the ability to create and open the database. ' - but it sounds to me more like the server cannot be found.
Is this an existing server, or fairly new server?
Is there a connection document in the user's local address book for the server, typically in the format ' SomeDominoServer/Domain'?
Does the connection doc specify a fqdn, or an IP address?
From the notes client, can you 'ctrl-o' and open the server?
In the agent, are you specifying 'SomeDominoServer/Domain', or just 'SomeDominoServer'?
Is ' dbName' located in the data directory or 'SomeDominoServer/Domain'? Or is it located in a subdirectory?
Have you enabled to lotusscript debugger and walked thru the agent? When you hit the line ' If db.IsOpen() ' - does db have a value?