joomla component error

[mj1256]

this is not a joomlart issue, but I hope that another joomla guru can help me.

I want to use the tutorials component on a 1.5.2 site, according to the threads on joomla it works OK

I get an error message

Fatal error: Class 'InputFilter' not found in /home/xxxxx/public_html/components/com_tutorials/tutorials.class.php on line 68


this is the associated line of code


// specific filters
$iFilter = new InputFilter();

if ($iFilter->badAttributeValue( array( 'href', $this->url ))) {
$this->_error = addslashes( _TUT_MOSTUT_VALID_URL );
return false;
}

can anyone help?