See the updated testNG xml file and still getting the same error.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "
http://testng.org/testng-1.0.dtd">
<suite name="Test-class Suite" >
<listeners>
<listener class-name="com.zoopla.qa.extendreport.ExtendReport" />
</listeners>
<test thread-count="1" name="Test">
<classes>
<class name="com.zoopla.qa.testcase.PracticeOne" />
<class name="com.zoopla.qa.testcase.PracticeTwo" />
<!-- <class name="com.zoopla.qa.testcase.HomePageTest" /> <class name="com.zoopla.qa.testcase.PropertyPageTest"
/> <class name="com.zoopla.qa.testcase.SalePageTest" /> <class name="com.zoopla.qa.testcase.AgentDetailsPageTest"
/> -->
</classes>
</test>
</suite>