NS runtime problems

[Jonah Petri <jpetri@sitaranetworks.com>]

Any help on this issue would be greatly appreciated.
I am having trouble running NS.  The ns-allinone package compiles fine,
but when I run ns:

$ ns example1.tcl

I get this:

invalid command name: "simulator"
    while executing
"simulator create _o3 "
    invoked from within
"catch "$className create $o $args" msg"
    (procedure "new" line 3)
    invoked from within
"new simulator"
    (file example1.tcl line1)

I looked at the Installation problems page, which contained a
discription of this exact problem and the solution, which is to make
sure tclsh is in my path.  The trouble is,

$which tclsh
yields:  /usr/bin/tclsh, which is a symbolic link to /usr/bin/tclsh8.0

I also checked my ns makefile which contained the line:
TCLSH  = tclsh8.0
which seems to be correct.  Can anyone give me some help on this issue?
My machine is a P166 running Red Hat Linux 5.0.

Thanks,
    Jonah Petri
    jpetri@sitaranetworks.com