Export pivot table to Excel gives error: missing tag row (with an unwanted tag INSERT)

Question

I am building a WPF application which uses OWC pivot table to display some data. When I click the built-in button to export the pivot table to excel, it writes to the log file with such error message:

XML ERROR in PivotTable
REASON: Missing Tag
ACTION: Aborting current XML group
FILE:   C:\Users\MY_NAME\AppData\Local\Temp\PivotTable71147_cachedata.xml
GROUP:  PivotCache
TAG:    row

When I open PivotTable71147_cachedata.xml file, it looks like this:

<xml xmlns:s='uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882'
xmlns:dt='uuid:C2F41010-65B3-11d1-A29F-00AA00C14882'
xmlns:rs='urn:schemas-microsoft-com:rowset'
xmlns:z='#RowsetSchema'>
    <s:Schema id='RowsetSchema'>
    <s:ElementType name='row' content='eltOnly' rs:updatable='true'>
    <s:AttributeType name='RecID' rs:number='1' rs:write='true'>
        <s:datatype dt:type='int' dt:maxLength='4' rs:precision='0' rs:fixedlength='true' rs:maybenull='false'/>
    </s:AttributeType>
            <s:extends type='rs:rowbase'/>
    </s:ElementType>
    </s:Schema>
    <rs:data>
    <rs:insert>
    <z:row RecID='1'/>
    <z:row RecID='2'/>
        </rs:insert>
    </rs:data>
</xml>

I am not an expert on pivot table format, but here in this example there are indeed two rows to be inserted, which have all the row data (RecID is the only column element). And I compared with some online .xml example, as well as the schema for rs:data schema, it seems that this element is not supposed to be there, i.e., should directly have multiple elements as children elements. But why do I have this rs:insert ?

UPDATED:

In this example I am using OWC11. Should I try OWC10 instead (or is it because some version mismatch)? Because in one of our MS Access application we are using OWC10 and the Export to Excel function works fine. But I have some problem using OWC10 in .NET.