XML : Can't run test cases parallel from TestNG xml?

I was trying to run the test cases parallel but when i execute the code it launches 2 browser session & test cases run one after another. Also i want to run test cases of one class parallel in different thread. Can someone please explain me where exactly we use invocation count?? Below is the xml file (1st for multiple class & second for single class) i am using.

1 xml:

   <?xml version="1.0" encoding="UTF-8"?>      <!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">      <suite name="Suite" parallel="classes" thread-count="3" verbose="8" >        <test name="Test" >           <classes>            <class name="com.test.script1"/>  <class name="com.test.script2"/>        </classes>      </test>   </suite>     

2 xml:

  <?xml version="1.0" encoding="UTF-8"?>      <!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">      <suite name="Suite" parallel="methods" thread-count="3" verbose="8" >        <test name="Test" parallel="tests" thread-count="3" >           <classes>            <class name="com..test.script1"/>        </classes>      </test>   </suite>