I pasted it into the eCart Object exactly as you'd posted it...weird. :(
When I add the single quote:
$itmObj->Inventory = abs($itmObj->Quantity > $itmObj->AvailableQuantity)?$itmObj->Quantity = $itmObj->AvailableQuantity:";//I
I'm getting syntax errors all over the place in the rest of the LEDCart_PHP.php file.