DB schema with initial DB content is in CC package:
upload/install/db/schema.inc.php
Restoring depends to how many countries you want to get back.
IF few just rip appropriate INSERT lines like
$db->misc("INSERT INTO `".$_POST['dbprefix']."CubeCart_iso_countries` VALUES (238, 'ZM', 'Zambia', 'ZMB', 894);");
make proper SQL, run it in MyPhpAdmin ....
-----------------------------------------------
IF all, prepare and upload sritpt like this:
<?php
include_once("includes/ini.inc.php");
include_once("includes/global.inc.php");
include_once("classes/db.inc.php");
$db = new db();
// rip all countries, counties lines here like
$db->misc("INSERT INTO `".$_POST['dbprefix']."CubeCart_iso_countries` VALUES (1, 'AF', 'Afghanistan', 'AFG', 4);");
$db->misc("INSERT INTO `".$_POST['dbprefix']."CubeCart_iso_countries` VALUES (2, 'AL', 'Albania', 'ALB', 8);");
$db->misc("INSERT INTO `".$_POST['dbprefix']."CubeCart_iso_countries` VALUES (3, 'DZ', 'Algeria', 'DZA', 12);");
.
.
.
.
.
?>
Empty CubeCart_iso_countries(counties) table contents and run your script.
Hope all is clear :)