Something

atchoum# ldd /usr/local/lib/nspluginwrapper/i386/linux/npviewer.bin
/usr/local/lib/nspluginwrapper/i386/linux/npviewer.bin:
        libgtk-x11-2.0.so.0 => not found
        libgdk-x11-2.0.so.0 => not found
        libgobject-2.0.so.0 => not found
        libdl.so.2 => /lib/libdl.so.2 (0x2807e000)
        libglib-2.0.so.0 => not found
        libX11.so.6 => /usr/X11R6/lib/libX11.so.6 (0x28082000)
        libXt.so.6 => /usr/X11R6/lib/libXt.so.6 (0x28156000)
        libpthread.so.0 => /lib/obsolete/linuxthreads/libpthread.so.0 (0x281ab000)
        libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x281fe000)
        libc.so.6 => /lib/obsolete/linuxthreads/libc.so.6 (0x28208000)
        /lib/ld-linux.so.2 (0x2805f000)
        libSM.so.6 => /usr/X11R6/lib/libSM.so.6 (0x28327000)
        libICE.so.6 => /usr/X11R6/lib/libICE.so.6 (0x28330000)


atchoum# ldconfig -r | grep libgtk-x11-2.0.so.0
        184:-lgtk-x11-2.0.0 => /usr/local/lib/libgtk-x11-2.0.so.0