java - Unable to analyse project with SonarQube -

i want analyse project sonarqube
while doing gives me error message saying

error during execution of sonar error status [command: c:\program files (x86)\java\jdk1.6.0_18\jre\bin\java.exe -cp c:\users\qfrg\appdata\local\temp\sonar-runner-impl7722306846094038579.jar org.sonar.runner.impl.batchlaunchermain c:\users\qfrg\appdata\local\temp\sonar-project6654886318444556353.properties]: 1

in console log see :

caused by: org.sonar.api.utils.sonarexception: plugin javascript not supported java 1.6.0_18
caused by: java.lang.unsupportedclassversionerror: org/sonar/plugins/javascript/javascriptplugin : unsupported major.minor version 51.0

i installed plugins findbugs, checkstyle, pmd , m2eclipse before installing sonarqube, after installing sonarqube, when tried add them again

unable connect repository http://eclipse-cs.sourceforge.net/update/compositecontent.xml connection http://eclipse-cs.sourceforge.net refused

please find version , plugin details:
java:

java version "1.6.0_18" java(tm) se runtime environment (build 1.6.0_18-b07) java hotspot(tm) client vm (build 16.0-b13, mixed mode, sharing)

maven:

apache maven 3.0.3 (r1075438; 2011-02-28 23:01:09+0530) maven home: c:\dev\apache-maven-3.0.3-bin java version: 1.6.0_18, vendor: sun microsystems inc. java home: c:\program files (x86)\java\jdk1.6.0_18\jre default locale: en_us, platform encoding: cp1252 os name: "windows 7", version: "6.1", arch: "x86", family: "windows"

and 

sonarqube server 4.5.4
eclipse : kepler service release 2

and using tfs source control going wrong ? problem java version ? as, have seen in sites worked them when upgraded 1.7 version of java

any appreciated

as mentionned in requirements documentation page, java 7 @ least required run sonarqube server , sonarqube analyses.

you using java 6 virtual machine, why error messages.