I'm getting 'Sequence contains no elements' when submitting the document below...
<eConnect xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<POPReceivingsType>
<eConnectProcessInfo xsi:nil="true" />
<taRequesterTrxDisabler_Items xsi:nil="true" />
<taUpdateCreateItemRcd xsi:nil="true" />
<taUpdateCreateVendorRcd xsi:nil="true" />
<taCreateVendorAddress_Items xsi:nil="true" />
<taPopRcptLotInsert_Items xsi:nil="true" />
<taPopRcptSerialInsert_Items xsi:nil="true" />
<taPopRcptLineInsert_Items>
<taPopRcptLineInsert>
<POPTYPE>1</POPTYPE>
<ITEMNMBR>JOE HOY-ADVANCE-H</ITEMNMBR>
<VENDORID>Joerns</VENDORID>
<VNDITNUM>JOE HOY-ADVANCE-H</VNDITNUM>
<QTYSHPPD>1</QTYSHPPD>
</taPopRcptLineInsert>
</taPopRcptLineInsert_Items>
<taPopRcptMultiBin_Items xsi:nil="true" />
<taPopRcptLineTaxInsert_Items xsi:nil="true" />
<taPopRctUserDefined xsi:nil="true" />
<taPopDistribution_Items xsi:nil="true" />
<taAnalyticsDistribution_Items xsi:nil="true" />
<taPopRcptHdrInsert>
<POPTYPE>1</POPTYPE>
<receiptdate>2/14/2012</receiptdate>
<BACHNUMB>ECON0214</BACHNUMB>
<VENDORID>Joerns</VENDORID>
</taPopRcptHdrInsert>
<taMdaUpdate_Items xsi:nil="true" />
</POPReceivingsType>
</eConnect>