build octomap using pointcloud2 data

edit

Honestly there does not seem to be anything wrong. That say we could use more info like command used or roslaunch file. If there is nothing wrong with your tf tree (you can check using rosrun tf view_frames) the only thing you need is to subscribe to the topic.
Anyhow if you only want to visualize the octomap just go to rviz and select a a MarkerArray message. If you need to process it in some way you might consider using the Octomap library or subscribing to the octomap_point_cloud_centers message.
In any case this is the type of roslaunch i use when working with octomap and a kinect:

<?xml version="1.0" encoding="UTF-8"?>
<launch>

  <node pkg="octomap_server" type="octomap_server_node" name="octomap_server">
   <param name="resolution" value="0.05"/>

    <!-- fixed map frame (set to 'map' if SLAM or localization running!) -->
    <param name="frame_id" type="string" value="map"/>

    <!-- maximum range to integrate (speedup!) -->
    <param name="sensor_model/max_range" value="4.0"/>
    <param name="base_frame_id " value="base_link" type="str"/>

    <!-- data source to integrate (PointCloud2) -->
    <remap from="cloud_in" to="/your/cloud/topic/here"/>

  </node>

</launch>