If you use login form in theme:
see
http://www.peak.ne.jp/xoops/modules/xhnewbb/viewtopic.php?topic_id=354&forum=3&post_id=13...Else if you use customized templates set:
edit system_block_login.html and insert this line manually.
<input type="checkbox" name="rememberme" value="On" class ="formButton" />
Else:
update system module in module's admin.
And I don't like "bump".
I often disregard "bump"ed questions