Problem solved.
it was a big bug...
this lines missing from components>com_virtuemart>views>category>view.html.php file:
find:
$ratingModel = VmModel::getModel('ratings');
$showRating = $ratingModel->showRating();
$this->assignRef('showRating', $showRating);
replace:
$ratingModel = VmModel::getModel('ratings');
$showRating = $ratingModel->showRating();
$this->assignRef('showRating', $showRating);
// added lines from components>com_virtuemart>views>productdetails>view.html.php
$rating = $ratingModel->getRatingByProduct($product->virtuemart_product_id);
$this->assignRef('rating', $rating);
Add this lines where you want to diplay stars: components>com_virtuemart>views>category>tmpl>default.php
<!-- The "Average Customer Rating" Part by Vapro -->
<?php
if($this->showRating){
$maxrating = VmConfig::get('vm_maximum_rating_scale',5);
$rating = empty($this->rating)? JText::_('COM_VIRTUEMART_RATING').' '.JText::_('COM_VIRTUEMART_UNRATED'):JText::_('COM_VIRTUEMART_RATING') . round($this->rating->rating, 2 ) . '/'. $maxrating;
$ratingwidth = ( $this->rating->rating * 100 ) / $maxrating;
?>
<span class="vote">
<?php echo $rating ?>
<br/>
<span title=" <?php echo (JText::_("COM_VIRTUEMART_RATING_TITLE") . $this->rating->rating . '/' . $maxrating) ?>" class="vmicon ratingbox" style="display:inline-block;">
<span class="stars-orange" style="width:<?php echo $ratingwidth;?>%">
</span>
</span>
</span>
<?php
//$img_url = JURI::root().VmConfig::get('assets_general_path').'/reviews/'.$product->votes->rating.'.gif';
//echo JHTML::image($img_url, $product->votes->rating.' '.JText::_('COM_VIRTUEMART_REVIEW_STARS'));
//echo JText::_('COM_VIRTUEMART_TOTAL_VOTES').": ". $product->votes->allvotes;
}?>