Hi Tully,

I have set ROBOT=sim in my environment, but this problem is still existed.
When I type the command, it shows as following:

jolin@ubuntu:~$ ldd
/opt/ros/cturtle/stacks/pr2_controllers/pr2_mechanism_controllers/lib/libpr2_mechanism_controllers.so


    linux-gate.so.1 =>  (0x00a2c000)
    libboost_filesystem.so.1.40.0 => /usr/lib/libboost_filesystem.so.1.40.0
(0x00bb7000)
    librobot_mechanism_controllers.so =>
/opt/ros/cturtle/stacks/pr2_controllers/robot_mechanism_controllers/lib/librobot_mechanism_controllers.so
(0x001d1000)
    libtf_conversions.so =>
/opt/ros/cturtle/stacks/geometry/tf_conversions/lib/libtf_conversions.so
(0x00d88000)
    libpr2_controller_manager.so =>
/opt/ros/cturtle/stacks/pr2_mechanism/pr2_controller_manager/lib/libpr2_controller_manager.so
(0x002e1000)
    libpr2_mechanism_model.so =>
/opt/ros/cturtle/stacks/pr2_mechanism/pr2_mechanism_model/lib/libpr2_mechanism_model.so
(0x00de7000)
    libkdl_parser.so =>
/opt/ros/cturtle/stacks/robot_model/kdl_parser/lib/libkdl_parser.so
(0x00b12000)
    liborocos-kdl.so.1.0 =>
/opt/ros/cturtle/stacks/geometry/kdl/lib/liborocos-kdl.so.1.0 (0x00f37000)
    liburdf.so => /opt/ros/cturtle/stacks/robot_model/urdf/lib/liburdf.so
(0x00861000)
    libcontrol_toolbox.so =>
/opt/ros/cturtle/stacks/pr2_controllers/control_toolbox/lib/libcontrol_toolbox.so
(0x003c2000)
    libtf.so => /opt/ros/cturtle/stacks/geometry/tf/lib/libtf.so
(0x0025d000)
    libsensor_msgs.so =>
/opt/ros/cturtle/stacks/common_msgs/sensor_msgs/lib/libsensor_msgs.so
(0x00ec3000)
    libBulletDynamics.so.2.76 =>
/opt/ros/cturtle/stacks/geometry/bullet/lib/libBulletDynamics.so.2.76
(0x00973000)
    libBulletCollision.so.2.76 =>
/opt/ros/cturtle/stacks/geometry/bullet/lib/libBulletCollision.so.2.76
(0x003d4000)
    libLinearMath.so.2.76 =>
/opt/ros/cturtle/stacks/geometry/bullet/lib/libLinearMath.so.2.76
(0x00afc000)
    libmessage_filters.so =>
/opt/ros/cturtle/ros/core/message_filters/lib/libmessage_filters.so
(0x002a8000)
    libpoco_lite.so =>
/opt/ros/cturtle/stacks/common/pluginlib/lib/libpoco_lite.so (0x00a9e000)
    libtinyxml.so => /opt/ros/cturtle/stacks/common/tinyxml/libtinyxml.so
(0x0090c000)
    librosrecorder.so =>
/opt/ros/cturtle/ros/tools/rosrecord/lib/librosrecorder.so (0x002ae000)
    librosbag.so => /opt/ros/cturtle/ros/tools/rosbag/lib/librosbag.so
(0x004b0000)
    libtopic_tools.so =>
/opt/ros/cturtle/ros/tools/topic_tools/lib/libtopic_tools.so (0x00375000)
    libros.so => /opt/ros/cturtle/ros/core/roscpp/lib/libros.so (0x00537000)
    libboost_signals.so.1.40.0 => /usr/lib/libboost_signals.so.1.40.0
(0x0034d000)
    libXmlRpc.so => /opt/ros/cturtle/ros/3rdparty/xmlrpcpp/lib/libXmlRpc.so
(0x009fd000)
    librosconsole.so =>
/opt/ros/cturtle/ros/core/rosconsole/lib/librosconsole.so (0x0037d000)
    libboost_thread.so.1.40.0 => /usr/lib/libboost_thread.so.1.40.0
(0x003a0000)
    liblog4cxx.so.10 => /usr/lib/liblog4cxx.so.10 (0x0068b000)
    libroslib.so => /opt/ros/cturtle/ros/core/roslib/lib/libroslib.so
(0x00b96000)
    librospack.so => /opt/ros/cturtle/ros/tools/rospack/lib/librospack.so
(0x0082a000)
    librosstack.so => /opt/ros/cturtle/ros/tools/rospack/lib/librosstack.so
(0x00361000)
    libboost_system.so.1.40.0 => /usr/lib/libboost_system.so.1.40.0
(0x00c1a000)
    libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00c1f000)
    libm.so.6 => /lib/tls/i686/cmov/libm.so.6 (0x00fd4000)
    libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x008be000)
    libpthread.so.0 => /lib/tls/i686/cmov/libpthread.so.0 (0x008dd000)
    libc.so.6 => /lib/tls/i686/cmov/libc.so.6 (0x00ffa000)
    librt.so.1 => /lib/tls/i686/cmov/librt.so.1 (0x00ed1000)
    libltdl.so.7 => /usr/lib/libltdl.so.7 (0x003b5000)
    libdl.so.2 => /lib/tls/i686/cmov/libdl.so.2 (0x002bf000)
    libboost_iostreams.so.1.40.0 => /usr/lib/libboost_iostreams.so.1.40.0
(0x008f6000)
    libbz2.so.1.0 => /lib/libbz2.so.1.0 (0x00923000)
    libboost_regex.so.1.40.0 => /usr/lib/libboost_regex.so.1.40.0
(0x16116000)
    libboost_program_options.so.1.40.0 =>
/usr/lib/libboost_program_options.so.1.40.0 (0x00a2d000)
    libaprutil-1.so.0 => /usr/lib/libaprutil-1.so.0 (0x00d9e000)
    libdb-4.8.so => /usr/lib/libdb-4.8.so (0x0b466000)
    libapr-1.so.0 => /usr/lib/libapr-1.so.0 (0x00935000)
    /lib/ld-linux.so.2 (0x002c4000)
    libz.so.1 => /lib/libz.so.1 (0x009ca000)
    libicudata.so.42 => /usr/lib/libicudata.so.42 (0xb68be000)
    libicui18n.so.42 => /usr/lib/libicui18n.so.42 (0x06bac000)
    libicuuc.so.42 => /usr/lib/libicuuc.so.42 (0x0276c000)
    libuuid.so.1 => /lib/libuuid.so.1 (0x00858000)
    libcrypt.so.1 => /lib/tls/i686/cmov/libcrypt.so.1 (0x00eff000)
    libexpat.so.1 => /lib/libexpat.so.1 (0x00a75000)

What happened to me? What should I do to solve this problem? And I am using
C-Turtle in Ubuntu 10.04. Thanks in advanced!