What have you tried?

Do you have:

use CGI::Carp qw(fatalsToBrowser); # Remove for production code
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I use an error reporting sub for reporting "standard" errors and dumping the CGI parameter list:

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;
}
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Have you tried wrapping your troublesome code in an eval:

eval {
    #troublesome stuff here
};

ShowError ($@) if $@;
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