When I run this manually in a terminal, I get the following output:

$ echo $?; echo $PWD; echo $?; echo $HA; echo $?
0
/home/MyDir/projects/perl/monks
0

0
[download]

When I run the perl code, I get:

$ perl test_prog.pl
0
/home/MyDir/projects/perl/monks
0

0
[download]

I find nothing weird in the code that you should return a 1, since the echo $HA as a shell command would only echo $HA or a blank line (if $HA is nothing), and thus be successful either way; hence, 0.

Hope that helped,
-v