For anyone who want url-friendly URLs , please modify :
showflat.inc.php , about line 1452 :
"facebookURL" => urlencode("{$config['FULL_URL']}/ubbthreads.php/topics/$facebookPost"),
"tweetURL" => "{$config['FULL_URL']}/ubbthreads.php/topics/$facebookPost",
And I hope the future version can honor the "Enable Spider-friendly URLs?" parameter in "Primary Settings -> Advanced Options"