error while launching the standalone.launch file of cmd_vel_mux package

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hello, i am getting the following error while launching the standalone.launch file of cmd_vel_mux package :-

I am using ROS-Fuerte on UBUNTU 12.04 LTS

[ERROR] [1414061735.184320701]: Failed to load nodelet [/velocity_multiplexer] of type [cmd_vel_mux/CmdVelMuxNodelet]: Failed to load library /home/cr-lab-tu/yujin_ocs/cmd_vel_mux/lib/libcmd_vel_mux_nodelet.so. Make sure that you are calling the PLUGINLIB_REGISTER_CLASS macro in the library code, and that names are consistent between this macro and your XML. Error string: Cannot load library: /home/cr-lab-tu/yujin_ocs/cmd_vel_mux/lib/libcmd_vel_mux_nodelet.so: wrong ELF class: ELFCLASS32
[FATAL] [1414061735.184647143]: Service call failed!

[velocity_multiplexer-2] process has died [pid 7153, exit code 255, cmd /opt/ros/fuerte/stacks/nodelet_core/nodelet/bin/nodelet load cmd_vel_mux/CmdVelMuxNodelet nodelet_manager cmd_vel_mux/mux_cmd_vel:=mobile_base/commands/velocity cmd_vel_mux/web_cmd_vel:=web_app_teleop cmd_vel_mux/key_cmd_vel:=key_cmd_vel velocity_multiplexer/amcl_pose:=amcl_pose velocity_multiplexer/move_base_simple/goal:=move_base_simple/goal __name:=velocity_multiplexer __log:=/home/cr-lab-tu/.ros/log/27a24a26-5a9e-11e4-bab8-2c27d7efa01b/velocity_multiplexer-2.log].
log file: /home/cr-lab-tu/.ros/log/27a24a26-5a9e-11e4-bab8-2c27d7efa01b/velocity_multiplexer-2*.log