Can't seem to get Psql and Exec to work together

I am trying to run Postgresql's psql using Exec() command.
The code is below

<?
 $convert_sql_2 = "\"C:\postgresql\bin\psql.exe -d Geoprocessing -f
C:\\postgresql\\bin\\g126.sql";
 exec($convert_sql_2,$ds);
?>

It didn't insert the data I hope it would. I tested it from the dos command
line and it works fine.
also i used
$convert_sql_2 = "\"C:\postgresql\bin\psql.exe --help";
passthru($convert_sql_2,$ds);
 It works, giving me the help options.

Nyon