php - SQL Server Prepared Statement saying invalid column count -

so i'm working on project here , i"m trying prepared statement can handle odd objects slashes , not raw data comes through. however, when go execute statement provides same error on , on again:

sqlstate: 07002 code: 0 message: [microsoft][sql server native client 11.0]count field incorrect or syntax error 

it says field count incorrect, checked variables , made sure supposed there, is. i'm little confused guess. note first time working sqlsrv prepared statements, awesome!

here code below:

<?php     $servername = "localhost";      $connectioninfo = array( "database"=>"devel", "uid"=>"root", "pwd"=>"");     $conn = sqlsrv_connect( $servername, $connectioninfo);     $error_message = "";     $xml = trim(file_get_contents('/file.xml'));     $xml = new simplexmlelement($xml);     $truck_number;     $date_time;     $speed;     $heading;     $gps_quality;     $latitude;     $longitude;     $location;     $fix_type;     $ignition;     $gps_odometer;     $gps_rolling_odometer;     $performx_odometer;     $performx_fuel;     $performx_speed;     $performx_idle;     $packet_id;       sqlsrv_begin_transaction($conn);     $error_count = 0;     $q = "insert eagle_devel.dbo.people_net (truck_number, date_time, speed, heading, gps_quality, latitude, longitude, location, fix_type, ignition, gps_odometer, gps_rolling_odometer,                  performx_odometer, performx_fuel, performx_speed, performx_idle, packet_id) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)";            $stmt = sqlsrv_prepare($conn, $q, array(&$truck_number, &$date_time, &$speed, &$heading, &$gps_quality, &$latitude, &$longitude, &$location, &$fix_type, &$ignition, &$gps_odometer, &$gps_rolling_odometer, &$performx_odometer, &$performx_fuel, &$performx_speed, &$performx_idle, &$packet_id));     foreach($xml->loc_history $loc_history){             $truck_number = $loc_history->truck_number;             $date_time = $loc_history->datetime;             $speed = $loc_history->speed;             $heading = $loc_history->heading;             $gps_quality = $loc_history->gps_quality;             $latitude = $loc_history->latitude;             $longitude = $loc_history->longitude;             $location = $loc_history->location;             $fix_type = $loc_history->fix_type;             $ignition = $loc_history->ignition;             $gps_odometer = $loc_history->gps_odometer;             $gps_rolling_odometer = $loc_history->gps_rolling_odometer;             $performx_odometer = $loc_history->performx_odometer;             $performx_fuel = $loc_history->performx_fuel;             $performx_speed = $loc_history->performx_speed;             $performx_idle = $loc_history->performx_idle;             $packet_id = $xml->packet_id;                  if(sqlsrv_execute($stmt) === false){                 $error_count++;                 if(($errors = sqlsrv_errors()) != null){                     foreach($errors $error){                         $error_message .= "sqlstate: ".$error['sqlstate']."<br>";                         $error_message .= "code: ".$error['code']."<br>";                         $error_message .= "message: ".$error['message']."<br><br>";                     }                 }             }     }     if($error_count)         sqlsrv_rollback($conn);     else         sqlsrv_commit($conn);      print $error_message; ?> 

update : told try , initialize variables before hand did , this.

sqlstate: imssp code: -16 message: invalid php type parameter 1 specified. 

i have no idea means i'm researching.