[PHP] Error?

[Steve Jackson]

I get the following error and I don't know why this is the code:

 if($new)
  {
    $details =  get_product_details($new);
    if($details["catid"])
      $target = "show_cat.php?catid=".$details["catid"];
//line 55 is the bracket below.
}
  $path = $PHP_SELF;
  $path = str_replace("show_cart.php", "", $path);


Error:

 Warning: Can only count STRING and INTEGER values! in
/www/u1255/shop_testing/show_cart.php on line 55

Any ideas? all I'm trying to do is pass a qty from a form?