Is this MYSQL or PHP Error? When mysql_fetch_array

I have an error like this :

Warning: mysql_fetch_array() expects parameter 1 to be resource, boolean given in C:\xampp\htdocs\lab\try.php on line 40

The query is :

$graphquery = mysql_query ("SELECT
  $cluster,
  SUM(IF(idx=3,1,0)) AS green,
  SUM(IF(idx=2,1,0)) AS yellow,
  SUM(IF(idx=1,1,0)) AS red
FROM (SELECT
        $cluster
        $xcond
        ,LEAST(999 $acond) idx 
      FROM table
      WHERE date >= '". $startDate ."'
          AND date <= '". $endDate ."'
          AND $regional = '$gregcond'
          AND $latitude IS NOT NULL 
      GROUP BY $cluster, $lac, $mainid
      HAVING $cluster IS NOT NULL
$paraxcond
      ) A
GROUP BY $cluster");

If I echo the query, it will be like this (no error, perfect result too btw) :

SELECT
  cluster,
  SUM(IF(idx=3,1,0)) AS green,
  SUM(IF(idx=2,1,0)) AS yellow,
  SUM(IF(idx=1,1,0)) AS red
FROM (SELECT
        cluster,
        ROUND(AVG(some_value_Index))    some_value_Index,
        LEAST(999, AVG(some_value_Index) )    idx
      FROM TABLE
      WHERE tanggal >= '2012-07-10'
          AND tanggal <= '2012-08-02'
          AND Regional = 'Regional_Example'
          AND Latitude IS NOT NULL
      GROUP BY cluster, Lac, ID
      HAVING cluster IS NOT NULL
          AND some_value_Index IN(3,2,1)) A
GROUP BY cluster

when I add mysql_error on that script, it sounds like this :

Incorrect parameter count in the call to native function 'LEAST'

And here is how I willing to use the MYSQL Query :

$row = mysql_fetch_array ($graphquery)

When I am ECHO the query and try it on SQLYOG or PHPMYADMIN there is no error contained, so Can anyone tell me where is the error please? Thanks!