[ns] Problems with Dynamics example

[Lee <yli@gpu.srv.ualberta.ca>]

Hi, 
After runing the example3.tcl on the ns tutorial webpage
I got the following info, 
(ns-allinone-2.1b6 but daily snapshot of ns-2 of yesterday)
Please tell me what the problem is. Thanks.

YL

 invalid command name ".model1.ctrl.tl.f.f.a": invalid command name
".model1.ctrl.tl.f.f.a"
    while executing
"$annoBox size"
    (procedure "_o3" line 4)
    (Animator update_annotations line 4)
    invoked from within
"$self update_annotations $now"
    (procedure "_o3" line 48)
    (Animator settime line 48)
    invoked from within
"$self settime [expr $now + $timeStep]"
    (procedure "_o3" line 4)
    (Animator nextFrame line 4)
    invoked from within
"$self nextFrame"
    (procedure "_o3" line 6)
    (Animator renderFrame line 6)
    invoked from within
"_o3 renderFrame"
    ("after" script)