Failed to load nodelet

[mountluoupc]

When I run "roslaunch phidgets_imu imu.launch", I got

Failed to load nodelet [/ImuFilterNodelet] of type [imu_filter_madgwick/ImuFilterNodelet] even after refreshing the cache: According to the loaded plugin descriptions the class imu_filter_madgwick/ImuFilterNodelet with base class type nodelet::Nodelet does not exist. Declared types are phidgets_imu/PhidgetsImuNodelet

Any ideas?