解決方法：

打開 /include/arc.taglist.class.php 搜索

 //更新Tag信息

大概在 137行左右，把它上面的這3行代碼

$cquery = "SELECT COUNT(*) AS dd FROM `#@__taglist` WHERE tid = '{$this->TagInfos['id']}' AND arcrank >-1 ";
$row = $this->dsql->GetOne($cquery);
$this->TotalResult = $row['dd'];

修改為：

$this->dsql->SetQuery("SELECT aid FROM `#@__taglist` WHERE tid = '{$this->TagInfos['id']}' AND arcrank>-1 ");
$this->dsql->Execute();
while($row=$this->dsql->GetArray())
{
	$atrow = $this->dsql->GetOne("SELECT id FROM `#@__arctiny` WHERE id='{$row['aid']}' AND arcrank>-1");
	if(!is_array($atrow))
	{
		$this->dsql->ExecuteNoneQuery("DELETE FROM `#@__taglist` WHERE aid='{$row['aid']}' ");
		continue;
	}
	$idlists .= ($idlists=='' ? $row['aid'] : ','.$row['aid']);
}
if($idlists!=='') $this->TotalResult = $row['dd'] = count(explode(',',$idlists));

解決。