An identical element or attribute value was submitted multiple times. For help on how to proceed, see http://sellercentral.amazon.co.uk/gp/help/23801
If you submit inventory files to manage your product data, this error generally occurs when you provide the same value in two related columns. For example, this error occurs if you place the value "bowling" in both the used-for1 and used-for3 columns. Alternatively, you might have modified your inventory file so that it contains two columns with identical headings. To fix this error, remove duplicate values and ensure that each column heading matches the original template.
If you receive this error after posting an XML feed, you likely included an redundant element for the related SKU. Alternatively, you might have provided the same value more than once for a single element. To fix this error, remove duplicate elements or attribute values.