All right, I think I am making progess.... I ran the script from the command line, (using the suggestion from Sifmole, thank you)

To avoid "use of unintialized value" errors, I had to add some lines to check for NULL occurances of the form variables (and $TRACKER - which gave a NULL value from the command line{???}):

$TRACKER = $ENV{'HTTP_REFERER'};
if (!($TRACKER)) { $TRACKER = $ENV{'REMOTE_ADDR'};}
#added
if (!($TRACKER)) { $TRACKER = ""; }

# why would these ENV variables BOTH be blank ???

$client_email = $query->param('email');
#added
if (!($client_email)) { $client_email=""; }
chomp($client_email);

#added to other query vars...
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This seems somewhat redundant, BUT... those first few variables were happening BEFORE I sent the headers.

is there a better way to assure that the form values that are needed are not NULL before proceeding?