Input task

[Emil Alexandrov]

I get the following error when I try to use input task. 'Could not
create task of type: input. Common solutions are to use taskdef to
declare your task, or, if this is an optional task, to put the
optional.jar in the lib directory of your ant installation (ANT_HOME).'
My task is an optional one here is the code ...
<target ...>
    <input message="Do you want to get data from VSS (y/n)?"
           validargs="y,n"
           addproperty="doGetGromVSS"
    />
    <condition property="shouldGetFromVSS">
      <equals arg1="y" arg2="${doGetGromVSS}"/>
    </condition>
</target>

..and I do have optional.jar in my ANT_HOME\lib dir. What possibly can
be the problem? I'm using WinXP, jdk1.4 .

Thanks,
Emil