That message is indicating that the virtualisation server is unable to connect to your Alfresco server, which it requires in order to function correctly. The virt server will attempt to connect a number of times (20, from memory), sleeping in between each attempt, before giving up.
If your Alfresco server is up and running correctly, double check that the settings in ${ALFRESCO_HOME}/virtual-tomcat/conf/alfresco-shared.properties and ${ALFRESCO_HOME}/virtual-tomcat/conf/alfresco-virtserver.properties are correct. In the first file you need to double check the hostname and port of the Alfresco server, and in the second file you need to double that the login credentials for your Alfresco server are correct.