java error

I was able to compile some java code but I get the error message. Any help would be appreciated.

C:\Users\Bill\Desktop\test>java JavaWekaJ48TestTrainPredCsvVer
Exception in thread "main" java.lang.UnsupportedClassVersionError: JavaWekaJ48TestTrain
svVer : Unsupported major.minor version 51.0
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClassCond(Unknown Source)
        at java.lang.ClassLoader.defineClass(Unknown Source)
        at java.security.SecureClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.access$000(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
Could not find the main class: JavaWekaJ48TestTrainPredCsvVer.  Program will exit.


I was able to run a similar program called  JavaWekaJ48TestTrainPred which I then edited just a bit called JavaWekaJ48TestTrainPredCsvVer.

The edits were
1. Added in
import weka.core.converters.ConverterUtils.DataSource;

2. changed the commented part below to the uncommented:
     /*   BufferedReader readerTrain = new BufferedReader(
         new FileReader("C:/Program Files/Weka-3-7/data/weather.nominal.arff"));
        Instances dataTrain = new Instances(readerTrain);
        readerTrain.close();
            */
            DataSource sourceTrain = new DataSource("C:/Program Files/Weka-3-7/data/weather.nominal.csv");
 Instances dataTrain = sourceTrain.getDataSet();

3. changed the commented part below to the uncommented:
        /*BufferedReader readerTest = new BufferedReader(
         new FileReader("C:/Program Files/Weka-3-7/data/weather.nominalTest.arff"));
        Instances dataTest = new Instances(readerTest);
        readerTest.close();
            */
                  DataSource sourceTest = new DataSource("C:/Program Files/Weka-3-7/data/weather.nominal.csv");
 Instances dataTest = sourceTest.getDataSet();      

I am attaching the code.
My path variable looks like:
C:\Python27\;C:\Python27\Scripts;C:\Program Files\Common Files\Microsoft Shared\Windows Live;C:\Program Files\ActiveState Perl Dev Kit 9.0.1\bin\;%GTK_BASEPATH%\bin;C:\Perl\site\bin;C:\Perl\bin;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;C:\strawberry\c\bin;C:\strawberry\perl\site\bin;C:\strawberry\perl\bin;C:\Program Files\MySQL\MySQL Server 5.1\bin;C:\PROGRA~1\ADDINS~1\XLSTAT~1;C:\perl2exe;C:\Program Files\ActiveState Perl Dev Kit 9.0.1\bin;C:\Program Files\Windows Live\Shared;C:\Program Files\Microsoft SQL Server\100\Tools\Binn\;C:\Program Files\Microsoft SQL Server\100\DTS\Binn\;C:\Program Files\Java\jdk1.7.0_01\bin;C:\Program Files\Android\android-sdk\tools\;C:\Program Files\Calibre2\

my classpath looks like:
.;C:\Program Files\Weka-3-7\weka.jar;C:\Program Files\Java\jre6\lib\ext\QTJava.zip

Thanks!