Publishing tf from base_link to camera using Kinect error

edit

Hello, I'm publishing a tf from base_link to camera_rgb_optical_frame in order to calculate robot motion from camera motion. When doing this using a frame_tf_broadcaster similar to the one seen in the tf tutorials I get the following warning:

[ WARN] [1374775573.363920696]: TF exception:
Lookup would require extrapolation into the future.  Requested time 1374775573.291255712 but the latest data is at time 1374775573.259098846, when looking up transform from frame [/camera_depth_optical_frame] to frame [/camera_rgb_optical_frame]

So, when I look at the frames I see the following:

As you can see the frame tf broadcast is not being recognized.

Am I publishing to the correct frames (base_link -> camera_rgb_optical_frame)? Any idea why the tf isn't being recognized?

Thanks,

EDIT: adding the code of the frame_tf_broadcaster

#include <ros/ros.h>
#include <tf/transform_broadcaster.h>

int main(int argc, char** argv){
  ros::init(argc, argv, "my_tf_broadcaster");
  ros::NodeHandle node;

  tf::TransformBroadcaster br;
  tf::Transform transform;

  ros::Rate rate(10.0);
  while (node.ok()){
    transform.setOrigin( tf::Vector3(0.0, 0.0, 2.0) );
    transform.setRotation( tf::Quaternion(0, 0, 0) );
    br.sendTransform(tf::StampedTransform(transform, ros::Time::now(), "base_link", "camera_rgb_optical_frame"));
    rate.sleep();
  }
  return 0;
};