Wvactive Form Widget

Error in wvactive form widget after installation
I have gone through wvactive and got help from http://www.yiiframework.com/extension/wvactiveform,
but one thing is missig there that after installation, I got error as follows:
Declaration of wvActiveForm::error() should be compatible with that of CActiveForm::error()

To fix this, I copied signature of CActiveForm into the wvActiveForm like below:
function error($model,$attribute,$htmlOptions=array(),$enableAjaxValidation=true,$enableClientValidation=true)
{
....
....
}
And after this It works fine, but I want to know, did I make a mistake somewhere?