JDBC receiver error

Hi

can you help? I'm getting the following error while trying to use the JDBC adaptor as a receiver

FATAL ERROR document format: structure 'Statement', key element 'UPRN' contains no values

I'm trying to do a SELECT

The message format that I'm sending is

<?xml version="1.0" encoding="UTF-8" ?>

- <ns0:mt_read_llpg_xml_backend xmlns:ns0="URN:SCC:PropertyAddress:1.0">

- <Statement>

- <dbTableName action="SELECT">

<table>LLPG_ALL</table>

</dbTableName>

- <access>

<UPRN />

<USRN />

<PAO_Start_Number />

<SAO_Start_Number />

<Street_Descriptor />

<Locality_Name />

<Town_Name />

<PostCode />

<WardOrParish />

<Parish_Code />

<X_Coordinate />

<Y_Coordinate />

</access>

- <key>

<UPRN compareOperation="EQ">45083411</UPRN>

</key>

</Statement>

</ns0:mt_read_llpg_xml_backend>