How to install libXm on Fedora 16

error while loading shared libraries: libXm.so.3

To get the libXm library you need to get OpenMotif package, which is available from the RPMFusion repository.

Fire up a terminal:

sudo yum install wget

RPM Fusion provides software that the Fedora Project or Red Hat doesn't want to ship.

wget http://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-stable.noarch.rpm 
wget http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-stable.noarch.rpm
sudo rpm -if rpmfusion-free-release-stable.noarch.rpm rpmfusion-nonfree-release-stable.noarch.rpm

Motif is the industry standard toolkit for UNIX systems and Open Motif, based on the Motif source code, provides a freely available version for open source developers.

sudo yum install openmotif.x86_64

Now just link the package to where it should usually be found:

sudo ln -s /usr/lib64/openmotif/libXm.so.4 /lib64/libXm.so.3

P.S.: You can always use yum whatprovides *missing_library_name.so to see what package provides a missing library.