init the xmlrpcValue from .xml file failed~

init xmlrpcValue with .xml failed.

`int main()
{
    std::string dir = "laser_filters.xml";
    int offset = 0;
    XmlRpcValue structXml;
    if(!structXml.fromXml(dir, &offset)){
       printf("XML FAIL");
     return 0;
    }
    retutn 0;
}`

always "XML FAIL",enter image description here