In version 2.63 of plugin there are a few spots that give warnings about the undefined index. I only mention this in case if might help you with improving the plugin.
I have warnings on because I'm in development mode.
Down around line 185 add something like:
if (isset($backup_options['repair']) && isset($backup_options['repair_period'])) {
$repair = intval($backup_options['repair'])*intval($backup_options['repair_period']);
} else {
$repair = 0;
}
Then around line 400 modify the line to be:
if(isset($_POST['Submit']) && $_POST['Submit']) {