oracle audit vault agent

Have you checked the docs?

http://docs.oracle.com/cd/E13850_01/doc.102/e13839/avgnt_agent_install.htm#CIHICEBD

db_name portion is the Oracle Audit Vault name specified during the Audit Vault Server installation, which is the global name

yeah, go for the oracle docs as slightwv suggested, those are the best places for all these FAQ's

I understand that you are installing the agent.. but the agent will connect to server, so you have to specify the service name of the server to which the agent connects(SID/Service name is the SID of Oracle Audit vault server..)

also check this link, which have brief steps of the installation of both server and client

http://easyoradba.wordpress.com/2011/02/28/oracle-audit-vault-10-2-0-3-installation-and-configuration/

still stuck at the connect string

host:port:service name

Oracle audit vault server is installed on : mach1    
                                                          SID:ORCLT

Installing oracle Audit Vault on Mach2:

./runInstaller
...
.........
....
....

Connect String  :  hostname:Port: Service Name)
                            mach1:1521:ORCLT

Error:  verify connection string

mach1:1521:ORCLT
                                       
even after giving the above entry.. you got the error??

are machines mach1 and mach2 able to communicate with each other..

check whether there are any firewalls which are blocking the communication on port 1521 between machines..

Thanks