Your StandardPrice/item-price value is invalid. It must be a positive value. For help fixing this, see http://sellercentral.amazon.co.uk/gp/help/24861
If you received this error after uploading an inventory file, your item-price value is invalid.
If you received this error after posting a price feed (XML), your StandardPrice value is invalid.
To be valid, your item-price or StandardPrice value must be a positive value. For example, "3.00" is a valid value, but "-3.00" is invalid.
To resolve this error, please resubmit your data using an item-price or StandardPrice value that is greater than zero.