my @fields = qw(
    ict_category
    ict_type
    ict_subtype
    ict_instance
    ict_assign2_grp
    ict_severity_lvl
    ict_date
);
my @placeholders = map {'?'} @fields;
{ local $" = ',';
  $sqlwi = "INSERT INTO $ICT (@fields) 
  VALUES(@placeholders)";
}

$dbh->{RaiseError} = 1;
eval {
    my $sth = $dbh->prepare($sqlwi);
    $sth->execute(
        $a_catg,
        $a_type,
        $a_styp,
        $a_inst,
        $a_agrp,
        $a_sevl,
        $dat3,
    );
};
if ($@) {
  # unable to insert, error message is in $@
  ...
}