NS2.31 NAM problem - "[code omitted because of length]"

Problem: While executing NAM in NS2 following error appears.

nam:
[code omitted because of length]
: no event type or button # or keysym
while executing
"bind Listbox {
%W yview scroll [expr {- (%D / 120) * 4}] units
}"
invoked from within
"if {[tk windowingsystem] eq "classic" || [tk windowingsystem] eq "aqua"} {
bind Listbox {
%W yview scroll [expr {- (%D)}] units
}
bind Li..."

Solution:

1. Download "tk-8.4-lastevent.patch" patch file from http://bugs.gentoo.org/show_bug.cgi?id=225999
2. Save the file in tk8.4.x floder (remember that there could be tk8.4.14 or tk8.4.18)
3. Patch the file with this command

patch -p1 < ./tk-8.4-lastevent.patch

4. install again (with ./install command)

Now it works perfectly.

(If there is a problem on patching, change -p1 to -p0. )