The Order of your XML matters. I was getting the same error when I was doing the follow two commands.
<taPopRcptLineInsert_Items />
<taPopRcptLotInsert_Items />
and the answer is to match the below xml schema perfectly for order. So you would go
<taPopRcptLotInsert_Items />
<taPopRcptLineInsert_Items />
in my case.... Here is the full order for POPReceivingsType
<eConnect>
<POPReceivingsType>
<eConnectProcessInfo />
<taRequesterTrxDisabler_Items>
<taRequesterTrxDisabler />
</taRequesterTrxDisabler_Items>
<taUpdateCreateItemRcd />
<taUpdateCreateVendorRcd />
<taCreateVendorAddress_Items>
<taCreateVendorAddress />
</taCreateVendorAddress_Items>
<taPopRcptLotInsert_Items>
<taPopRcptLotInsert />
</taPopRcptLotInsert_Items>
<taPopRcptSerialInsert_Items>
<taPopRcptSerialInsert />
</taPopRcptSerialInsert_Items>
<taPopRcptLineInsert_Items>
<taPopRcptLineInsert />
</taPopRcptLineInsert_Items>
<taPopRcptMultiBin_Items>
<taPopRcptMultiBin />
</taPopRcptMultiBin_Items>
<taPopRcptLineTaxInsert_Items>
<taPopRcptLineTaxInsert />
</taPopRcptLineTaxInsert_Items>
<taPopRcptUserDefined />
<taPopDistribution_Items>
<taPopDistribution />
</taPopDistribution_Items>
<taAnalyticsDistribution_Items>
<taAnalyticsDistribution />
</taAnalyticsDistribution_Items>
<taPopRcptHdrInsert />
<taMdaUpdate_Items>
<taMdaUpdate />
</taMdaUpdate_Items>
</POPReceivingsType>
</eConnect>
