Two things you need to define in your ant properties or build.xml file:
1. Define typeDef for your WSDL to Java utility so as to use in ant target

Java Syntax (Toggle Plain Text)

<typedef name="wsdl2java" classname="org.apache.axis.tools.ant.wsdl.Wsdl2javaAntTask" classpathref="axisclasspath"/>

<typedef name="wsdl2java" classname="org.apache.axis.tools.ant.wsdl.Wsdl2javaAntTask" classpathref="axisclasspath"/>

2. Within your desired target say

Java Syntax (Toggle Plain Text)

<wsdl2java verbose="true" output="${yourOutputDir}/wsdl" url="${wsdlFileName}.wsdl" deployScope="Session">
    <mapping package="${package}" namespace="urn:${service.name}"/>
</wsdl2java>

<wsdl2java verbose="true" output="${yourOutputDir}/wsdl" url="${wsdlFileName}.wsdl" deployScope="Session"> <mapping package="${package}" namespace="urn:${service.name}"/> </wsdl2java>

Make sure you have mentioned axisclasspath using <path id="axisclasspath">....</path>, which is required by step 1, this is the classpath which ant will internally use to compile WSDL to generate stubs and impl files, so make sure you have mentioned all necessary Axis jars in it.

Hope this will help.

no, it is NOT urgent.

The thing to do is to read the documentation, which explains it all in detail.
The steps for using ANT to retrieve the WSDL and generate your classes has already been outlined above though not every option you could use mentioned, use the manual to find out about those.