For vCO 5.1 you can check in {vCO_INSTALL_FOLDER}\configuration\jetty\logs\jetty.log
And log4j.configuration I believe is in {vCO_INSTALL_FOLDER}\configuration\jetty\resources\log4j.xml
For vCO 5.1 you can check in {vCO_INSTALL_FOLDER}\configuration\jetty\logs\jetty.log
And log4j.configuration I believe is in {vCO_INSTALL_FOLDER}\configuration\jetty\resources\log4j.xml