Problem with array object

Hi I have adapted a basket script to take products as objects, when I try to subtract a product from the basket array i get the above error, they look like this:
>>> to remove from basket
Product Object
(
[productId] => 3
[accessories] => Array
(
[0] => fab_prot
[1] => endcap
)

[productQuantity] => 0
)

>>> this is the existing basket
Array
(
[0] => Product Object
(
[productId] => 1
[accessories] => Array
(
)

[productQuantity] => 1
)

[1] => Product Object
(
[productId] => 3
[accessories] => Array
(
[0] => fab_prot
[1] => endcap
)

[productQuantity] => 0
)

)


This is the method/function i'm using:

function DeleteFromBasket($id)
{
echo "<pre>";
print_r($product = $this->getProduct($id)); //outputs the lines above
print_r($this->products);
echo "<pre>";
$this->products = array_diff($this->products, array($product));
return true;
}

Darren