Problem:
(1) pubDate of backend.php becomes a validator error, outside of the US.

error site
http://www.xoopscube.jp/backend.php
http://www.xoops.net.br/backend.php
http://www.xoopsmalaysia.org/backend.php
and more

check in here
http://feedvalidator.org/

(2) php function strtotime cannot parse pubDate of backend.php.
Timezone JST is ok, but BRST or SGT become an error.


Reason:
RFC822 does not define a timezone except GMT or North America.

http://www.faqs.org/rfcs/rfc822.html


Solution:
change code formatTimestamp in functuions.php.
r option is added since PHP 4.0.4