Hi,
Is odometry computed? Just tried:
$ roslaunch freenect_launch freenect.launch depth_registration:=true
# map over 30 nodes then kill rtabmap.launch
$ roslaunch rtabmap_ros rtabmap.launch
# launch again in localization mode and use TF for odometry:
$ roslaunch rtabmap_ros rtabmap.launch localization:=true odom_frame_id:=odom
and no problems...