PHP fatal error and blank main_page=checkout_confirmation

I'm new to zen cart and can't seem to get my website working... using IDEAL as the only payment option.
I'm getting a blank page on payment and have come across a PHP fatal error in the error logs:

PHP Fatal error: Cannot use object of type mysqli_result as array in /shop/includes/modules/payment/sisowideal.php, referer: /shop/index.php?main_page=checkout_confirmation

and this is what it is directing me to:
$content = array();
foreach($order_products as $order_product) {
$content[]=$order_product['products_model'] . ' x ' . $order_product['products_quantity'];
}

The url is http://www. b o s r e c y c l i n g .nl/
Is there something that I have not done, and any idea on how to sort this?

Apparently $order_products is set to a return value of a mysqli_result and is not further processed to provide/create it as an array. The function foreach (x as y) expects x to be an array.

Need to use a loop checking if at the end of the "file". If not, then do action, move to the next record and continue until all records have been processed.

The sisow module has IMHO always been a little buggy. I prefer using this module for sisow instead.
If you give me a link to the siow module you used, I can take a look at it and maybe fix it

Thanks for the swift reply!

Need to use a loop checking if at the end of the "file". If not, then do action, move to the next record and continue until all records have been processed.
Sorry for my ignorance but how would you do that?

I think that what mc12345678 meant is:

$content = array();
while (!$order_products->EOF) {
  $content[]=$order_products->fields['products_model'] . ' x ' . $order_products->fields['products_quantity'];
  $order_products->MoveNext();
}