eval { require MyModule }
    if (defined $MyModule::Error) {
        print "Couldn't load MyModule: ", $MyModule::Error->{message}, "\n";
        # ...
    }

##</code><code>##

package MyModule;

our $Error;

# ...

if ($some_error) {
    $Error = {err = 42, message => 'Sorry, my fault!'};
    die;
    # or maybe just 'return 0;'
}