RSS & question

So I’ve almost got all my RSS issues worked out except it generates one error:

line 20, column 42: Incorrect day of week: Wed [help]
<pubDate>Wed, 11 Aug 2006 13:48:47 MST</pubDate>

now… upon clicking the help button it sends me to… this nice “help” doc

so… my questions is… what’s the flippin difference between what I have… the incorrect example they give… and the correct one. Cause I’m surely not seeing it