sub showError {
    my $err = shift;

    print header();
    print start_html("IsosimCGI_Error");
    print h1("IsosimCGI Error");
    print p ($err);
    
    my %params = Vars ();
    for my $param (keys %params) {
        print br ("$param -> $params{$param}");
    }
    
    print end_html();
    exit 1;
}