script not working in php

Hi,

this works ok in pgadmin3

select name[i], kw[i]
from ( select generate_series(1,6) as i, 
              array['Biomasse', 'Deponiegas', 'Solar', 'Wasser', 'Wind','GESAMT'] as name, 
              array[biomasse_kw, deponiegas_kw, solar_kw,wasser_kw, wind_kw, kw] as kw
       from energie.tennet_auswertung_pivot_energie ) z
;

but in the php script I get error 500?

$result = pg_query($connection,'
select name[i], kw[i]
from ( select generate_series(1,6) as i, 
              array['Biomasse', 'Deponiegas', 'Solar', 'Wasser', 'Wind','GESAMT'] as name, 
              array[biomasse_kw, deponiegas_kw, solar_kw,wasser_kw, wind_kw, kw] as kw
       from energie.tennet_auswertung_pivot_energie ) z
;
'); 

$rows = array();
while($r = pg_fetch_assoc($result)) {
    $rows[] = $r;
}

print json_encode(array_values(pg_fetch_all($result)));

can anyone explain whythis is happening?

thanks,

Rob