UT theoretical chemistry code forum

hello:
I'm a new user from china, now I come across a problem. When I input the order
chgsum.pl AECCAR0 AECCAR2
it say: chgsum.pl: command not found
I chmod the chgsum.pl before input the order.
I download the chgsum.pl script from this website.
who can tell me why!
thanks!
PS:forgive my poor English.

Download all the scripts and put the directory in your path. You should only need to have perl (and env) installed for this script to run.

try:
perl chgsum.pl AECCAR0 AECCAR2