confused with IceXML

I'm working on a xml2freezedb module,which read xml data from a xml file,and write them into freeze evictor or map db.
for example,if the slice:

module Demo
{
   struct hello
   {
      int a;
      float b;
      string c;
   };

};

if the freeze map 's key is int, the value is ::Demo::hello then the xml file will like this:

<database>
<record>
     <key>1</key>
     <value>
          <a>1</a>
          <b>3.14</b>
          <c>xml2db</c>
     </value>
</record>
</database>

and I write a xmltest.cpp to test the parser's output:

#include <IceXML/Parser.h>
#include <iostream>
using namespace std;
using namespace IceXML;

void dumpXML(NodePtr node)
{
    cout << "<" << node->getName() << ">" << endl;
    NodeList nodes = node->getChildren();
    if( nodes.empty() )
    {
        cout << node->getValue() << endl;
    }
    else
    {
       for(int i = 0;i < nodes.size() ;i++)
       {
          dumpXML(nodes[i]);
       }
    }
    cout << "</" << node->getName() << ">" << endl;
}
int main(int argc,char** argv)
{
    DocumentPtr xml = IceXML::Parser::parse(argv[1]);
    dumpXML(xml);
   return 0;
}

But the output has many empty xml elements:

<>
<database>
<>


</>
<record>
<>

</>
<>


</>
<>

</>
<key>
<>
1
</>
</key>
<>

</>
<>


</>
<>

</>
<value>
<>

</>
<>


</>
<>

</>
<a>
<>
1
</>
</a>
<>

</>
<>


</>
<>

</>
<b>
<>
3.14
</>
</b>
<>

</>
<>


</>
<>

</>
<c>
<>
xml2db
</>
</c>
<>

</>
<>


</>
<>

</>
</value>
<>

</>
<>


</>
</record>
<>


</>
</database>
</>

If this is not a IceXML::DocumentBuilder's bug,then what's the IceXML real meaning?