Unable to select XElements with LINQ

I'm trying to select nodes using LINQ but I cannot understand why this simple query does not work.

My xml is like this:

<config>
  <func_list current_app="GSCC" flag="0">
    <func id="GSCC">
      <BLOCKS>
        <BLOCK id="1" type="ACTIONS">
          <ITEMS>
            <ITEM id="1" type="UINT32" size="1" value="1" />
            <ITEM id="2" type="UINT32" size="1" value="5" />
            <ITEM id="3" type="UINT32" size="1" value="0" />
          </ITEMS>
        </BLOCK>
      </BLOCKS>
    </func>
  </func_list>
</config>

Now, I have an XElement (_funcNode) which points to 'func' node:

IEnumerable<XElement> xBlocks = from el in _funcNode.Descendants("BLOCK")
                                where el.Attribute("type").Value == "ACTIONS"
                                select el;

if (!xBlocks.Any()) return false;

Also the xBlocks.Any() throws an System.NullReferenceException exception. Any idea?