The visp tracker example when started with tutorial.launch gives the following error

[ERROR] [1496752518.116357091]: Failed to load nodelet [/trackermbt] of type [visptracker/Tracker] even after refreshing the cache: Failed to load library /opt/ros/indigo/lib//libtrackerNodelet.so. Make sure that you are calling the PLUGINLIBEXPORTCLASS macro in the library code, and that names are consistent between this macro and your XML. Error string: Could not load library (Poco exception = libvisp_mbt.so.3.0: cannot open shared object file: No such file or directory)

Pl. help/