Theme Options - Not working #2 :(

function theme_options_validate( $input ) {
    // global $select_options, $radio_options;

    // Change to integer
    $input['slidercount'] = (int)$input['slidercount'];
    if ($input['slidercount'] < 1 || $input['slidercount'] > 50)
        $input['slidercount'] = 10;

    // Make array from string, remove duplicates, change all values to integer, remove non existing categories, make string from array
    if ($input['slidercats'] != '') {
        $slidercats = $input['slidercats'];
        $slidercats_array = explode( ',', $slidercats );
        $slidercats_array = array_unique( $slidercats_array );
        $slidercats_array = array_map('intval', $slidercats_array );

        foreach($slidercats_array AS $i => $value)
        {
            $cat = term_exists($i, 'category'); // cat_ID
            if ( ! $cat )
                unset($slidercats_array[$i]);
        }

        $input['slidercats'] = implode(",", $slidercats_array);

    }

    return $input;
}