Got the same problem today aswell and fixed it. I will post a update MySQL5-fix-file on the contributions download place, but I'm too busy right now so here's the little code snippet of the fix for index.php (around line 175):
// We are asked to show only a specific category
//BEGIN EDIT by AMS: contribution Quantity Pricebreaks per Product
//org: $listing_sql = "select" . $select_column_list . " p.products_id, p.manufacturers_id, p.products_price, p.products_tax_class_id, IF(s.status, s.specials_new_products_price, NULL) as specials_new_products_price, IF(s.status, s.specials_new_products_price, p.products_price) as final_price from " . TABLE_PRODUCTS . " p left join " . TABLE_SPECIALS . " s on p.products_id = s.products_id, " . TABLE_PRODUCTS_DESCRIPTION . " pd, " . TABLE_MANUFACTURERS . " m, " . TABLE_PRODUCTS_TO_CATEGORIES . " p2c where p.products_status = '1' and p.manufacturers_id = m.manufacturers_id and m.manufacturers_id = '" . (int)$HTTP_GET_VARS['manufacturers_id'] . "' and p.products_id = p2c.products_id and pd.products_id = p2c.products_id and pd.language_id = '" . (int)$languages_id . "' and p2c.categories_id = '" . (int)$HTTP_GET_VARS['filter_id'] . "'";
//QPBPP MySQL 5 compatible
$listing_sql = "select " . $select_column_list . " p.products_id, p.manufacturers_id, p.products_price, p.products_price1, p.products_price2, p.products_price3, p.products_price4, p.products_price5, p.products_price6, p.products_price7, p.products_price8, p.products_price1_qty, p.products_price2_qty, p.products_price3_qty, p.products_price4_qty, p.products_price5_qty, p.products_price6_qty, p.products_price7_qty, p.products_price8_qty, p.products_qty_blocks, p.products_tax_class_id, IF(s.status, s.specials_new_products_price, NULL) as specials_new_products_price, IF(s.status, s.specials_new_products_price, p.products_price) as final_price from " . TABLE_PRODUCTS . " p left join " . TABLE_SPECIALS . " s on p.products_id = s.products_id, " . TABLE_PRODUCTS_DESCRIPTION . " pd, " . TABLE_MANUFACTURERS . " m, " . TABLE_PRODUCTS_TO_CATEGORIES . " p2c where p.products_status = '1' and p.manufacturers_id = m.manufacturers_id and m.manufacturers_id = '" . (int)$HTTP_GET_VARS['manufacturers_id'] . "' and p.products_id = p2c.products_id and pd.products_id = p2c.products_id and pd.language_id = '" . (int)$languages_id . "' and p2c.categories_id = '" . (int)$HTTP_GET_VARS['filter_id'] . "'";
} else {
// We show them all
//org: $listing_sql = "select " . $select_column_list . " p.products_id, p.manufacturers_id, p.products_price, p.products_tax_class_id, IF(s.status, s.specials_new_products_price, NULL) as specials_new_products_price, IF(s.status, s.specials_new_products_price, p.products_price) as final_price from " . TABLE_PRODUCTS . " p left join " . TABLE_SPECIALS . " s on p.products_id = s.products_id, " . TABLE_PRODUCTS_DESCRIPTION . " pd, " . TABLE_MANUFACTURERS . " m where p.products_status = '1' and pd.products_id = p.products_id and pd.language_id = '" . (int)$languages_id . "' and p.manufacturers_id = m.manufacturers_id and m.manufacturers_id = '" . (int)$HTTP_GET_VARS['manufacturers_id'] . "'";
//QPBPP MySQL 5 compatible
$listing_sql = "select " . $select_column_list . " p.products_id, p.manufacturers_id, p.products_price, p.products_price1, p.products_price2, p.products_price3, p.products_price4, p.products_price5, p.products_price6, p.products_price7, p.products_price8, p.products_price1_qty, p.products_price2_qty, p.products_price3_qty, p.products_price4_qty, p.products_price5_qty, p.products_price6_qty, p.products_price7_qty, p.products_price8_qty, p.products_qty_blocks, p.products_tax_class_id, IF(s.status, s.specials_new_products_price, NULL) as specials_new_products_price, IF(s.status, s.specials_new_products_price, p.products_price) as final_price from " . TABLE_PRODUCTS . " p left join " . TABLE_SPECIALS . " s on p.products_id = s.products_id, " . TABLE_PRODUCTS_DESCRIPTION . " pd, " . TABLE_MANUFACTURERS . " m where p.products_status = '1' and pd.products_id = p.products_id and pd.language_id = '" . (int)$languages_id . "' and p.manufacturers_id = m.manufacturers_id and m.manufacturers_id = '" . (int)$HTTP_GET_VARS['manufacturers_id'] . "'";
}
} else {
// show the products in a given categorie
if (isset($HTTP_GET_VARS['filter_id']) && tep_not_null($HTTP_GET_VARS['filter_id'])) {
// We are asked to show only specific catgeory
//org: $listing_sql = "select " . $select_column_list . " p.products_id, p.manufacturers_id, p.products_price, p.products_tax_class_id, IF(s.status, s.specials_new_products_price, NULL) as specials_new_products_price, IF(s.status, s.specials_new_products_price, p.products_price) as final_price from " . TABLE_PRODUCTS . " p left join " . TABLE_SPECIALS . " s on p.products_id = s.products_id, " . TABLE_PRODUCTS_DESCRIPTION . " pd, " . TABLE_MANUFACTURERS . " m, " . TABLE_PRODUCTS_TO_CATEGORIES . " p2c where p.products_status = '1' and p.manufacturers_id = m.manufacturers_id and m.manufacturers_id = '" . (int)$HTTP_GET_VARS['filter_id'] . "' and p.products_id = p2c.products_id and pd.products_id = p2c.products_id and pd.language_id = '" . (int)$languages_id . "' and p2c.categories_id = '" . (int)$current_category_id . "'";
//QPBPP MySQL 5 compatible
$listing_sql = "select " . $select_column_list . " p.products_id, p.manufacturers_id, p.products_price, p.products_price1, p.products_price2, p.products_price3, p.products_price4, p.products_price5, p.products_price6, p.products_price7, p.products_price8, p.products_price1_qty, p.products_price2_qty, p.products_price3_qty, p.products_price4_qty, p.products_price5_qty, p.products_price6_qty, p.products_price7_qty, p.products_price8_qty, p.products_qty_blocks, p.products_tax_class_id, IF(s.status, s.specials_new_products_price, NULL) as specials_new_products_price, IF(s.status, s.specials_new_products_price, p.products_price) as final_price from " . TABLE_PRODUCTS . " p left join " . TABLE_SPECIALS . " s on p.products_id = s.products_id, " . TABLE_PRODUCTS_DESCRIPTION . " pd, " . TABLE_MANUFACTURERS . " m, " . TABLE_PRODUCTS_TO_CATEGORIES . " p2c where p.products_status = '1' and p.manufacturers_id = m.manufacturers_id and m.manufacturers_id = '" . (int)$HTTP_GET_VARS['filter_id'] . "' and p.products_id = p2c.products_id and pd.products_id = p2c.products_id and pd.language_id = '" . (int)$languages_id . "' and p2c.categories_id = '" . (int)$current_category_id . "'";
} else {
// We show them all
//org: $listing_sql = "select " . $select_column_list . " p.products_id, p.manufacturers_id, p.products_price, p.products_tax_class_id, IF(s.status, s.specials_new_products_price, NULL) as specials_new_products_price, IF(s.status, s.specials_new_products_price, p.products_price) as final_price from " . TABLE_PRODUCTS_DESCRIPTION . " pd, " . TABLE_PRODUCTS . " p left join " . TABLE_MANUFACTURERS . " m on p.manufacturers_id = m.manufacturers_id left join " . TABLE_SPECIALS . " s on p.products_id = s.products_id, " . TABLE_PRODUCTS_TO_CATEGORIES . " p2c where p.products_status = '1' and p.products_id = p2c.products_id and pd.products_id = p2c.products_id and pd.language_id = '" . (int)$languages_id . "' and p2c.categories_id = '" . (int)$current_category_id . "'";
//QPBPP MySQL 5 compatible
$listing_sql = "select " . $select_column_list . " p.products_id, p.manufacturers_id, p.products_price, p.products_price1, p.products_price2, p.products_price3, p.products_price4, p.products_price5, p.products_price6, p.products_price7, p.products_price8, p.products_price1_qty, p.products_price2_qty, p.products_price3_qty, p.products_price4_qty, p.products_price5_qty, p.products_price6_qty, p.products_price7_qty, p.products_price8_qty, p.products_qty_blocks, p.products_tax_class_id, IF(s.status, s.specials_new_products_price, NULL) as specials_new_products_price, IF(s.status, s.specials_new_products_price, p.products_price) as final_price from " . TABLE_PRODUCTS_DESCRIPTION . " pd, " . TABLE_PRODUCTS . " p left join " . TABLE_MANUFACTURERS . " m on p.manufacturers_id = m.manufacturers_id left join " . TABLE_SPECIALS . " s on p.products_id = s.products_id, " . TABLE_PRODUCTS_TO_CATEGORIES . " p2c where p.products_status = '1' and p.products_id = p2c.products_id and pd.products_id = p2c.products_id and pd.language_id = '" . (int)$languages_id . "' and p2c.categories_id = '" . (int)$current_category_id . "'";
//END EDIT by AMS: contribution Quantity Pricebreaks per Product
I hope this will help u aswell, I only tested it on a Linux server.
cheers.