loxilb UI: loxicmd save -a -c /var/ipfire/loxilb/ result in "Can't create dump file"

[vincentmli]

attempted to add loxicmd save -a -c /var/ipfire/loxilb/ from loxilb UI like below:

sub SaveLoxiConfig {
    my @save_options;
    my $command = 'loxicmd';
    my $dir="/var/ipfire/loxilb/";
    push(@save_options, "save", "-a", "-c", $dir);
    my @output = &General::system_output($command, @save_options);
    errormessage = join('', @output);
}

errormessage get "Can't create dump file"