BPC WebService with Xcelsius return zero data xml

Dear all,

   We follow the how-to guide to set up the the BPC web service for Xcelsius.

   When we call the url, we get a zero data xml like :

<data>
u2212<variable name="MyRange">
u2212<row><column>      </column><column>2007.INP</column></row>
u2212<row><column>LC</column><column>0</column></row></variable></data>

   It seems that some exceptions will cause the service fail to get data and generate a empty xml file. Sometimes , we got http 401 error and after refresh the page , the system generate the zero xml again.

    How do we set IIS or IE security for this to work?

Thanks,

Jeff