How to load .so library??

[CWen56 <n2688420@dec4000.cc.ncku.edu.tw>]

Hi! everyone advanced in NS
i am a fresh to NS and Linux
but i want to run some simulation about wireless
now i have setup up NS in Redhat6.0
everything seems OK but while running NS
it has the essages... libotcl.so not found
the following is what i check

[root@atmlab05 bin]# ldd ns
 libotcl.so => not found
 libtk8.2.so => not found
 libtcl8.2.so => not found
 libXext.so.6 => /usr/X11R6/lib/libXext.so.6 (0x4001b000)
 libX11.so.6 => /usr/X11R6/lib/libX11.so.6 (0x40026000)
 libnsl.so.1 => /lib/libnsl.so.1 (0x400c3000)
 libdl.so.2 => /lib/libdl.so.2 (0x400d8000)
 libstdc++-libc6.1-1.so.2 => /usr/lib/libstdc++-libc6.1-1.so.2
(0x400db00
0)
 libm.so.6 => /lib/libm.so.6 (0x4011d000)
 libc.so.6 => /lib/libc.so.6 (0x4013a000)
/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)

but that three files have already been put in /usr/local/lib
i try to use "ld" to load those .so files..
but even i read man of ld and try many ways , it is still in vain..
hope someone may help me and give me a hint how to load those three
files
thanks
regard