Uhd_find_devices error

Moving along with testing the system I wanted to see that the USRP2 was
being recognized. Whether I run uhd_find_devices or uhd_usrp_probe I get
the following error.

error while loading shared libraries: libboost_date_time.so.1.40.0:
cannot open shared object file: No such file or directory

What might the problem be here?

Thank you very much.