Rss feed "CEST" Error

[amsy]

I cant use the feedburner because of this reason.

if validated my rss feed with Feed Validator for Atom and RSS say this error

column 39: pubDate must be an RFC-822 date-time: Thu, 21 Aug 2008 17:22:50 CEST [help]

    <pubDate>Thu, 21 Aug 2008 17:22:50 CEST</pubDate>

and this,

line 457, column 0:Missing atom:link with rel="self" [help]

    </channel>

How can I fix thats problem