B2BEnterprise Package error

I get the following error from the service trying to publish an event to my Enterprise Broker:

Unable to open connection to host ‘’. Error ‘java.net.ConnectException: Connection refused: no further information’ was reported by the socket call.

What causes this error, and what is the best means of automatically responding to it?

I am using version 4.11 Enterprise Broker,
4.6 Integration Server, 4.6 B2BEnterprise Package.

Do you have webMethods Enterprise Broker: ServicePack # 3 for 4.1.1 GA (DOMESTIC) installed?

I had the Broker version wrong…it looks like I am at version 4.0.4p4 020501, which I believe is version 4.0 service pack 4.