Your description wasn't the issue. Your image includes #003170 and #592b01, neither of which are listed in the article.
@FrostPumpkin You were right!... You are used only 9 colors. I'm sorry to informed you wrong...
Yes, you're right. It's probably something with gifs. My PS (both CS2 and Elements) shows 25 colors when try to change the mode, even although I took only one layer... I finally manually checked the image and there's only 9 colors, soo my bad.
My piece doesn't appear! I got all the colors correct, but I didn't enter the right numbers in the description... 
Not sure how reliable this process is though, for some reason the PJ Specs is showing only 9 colors: http://yanrishatum.ru/pj/?input=http%3A%2F%2Fpixeljoint.com%2Fpixelart%2F106978.htm
Maybe your process works different for animated gifs?
When I want to see how much colors some image have, I start to convert color palette mode from rgb into "indexed color" (8-bit color palette). There you can see the number of used colors in the image... but, you probably know that...
Ahhh i didn't even read the rules entirely :O somehow skipped the 100x150px part haha. 25 colors count is weird tho, i used only listed in the description of my piece but heh - Not really a problem since dimensions doesn't fit anyways.
Thanks for your answer !
I think that's because (I checked) you used 25 colors instead of 9, and the image size is 208x248 instead of max. 100x150 as in the propositions. Too bad! I'm actually rooting for you even though and I participate...
Oh, my piece doesn't appear - I'm pretty sure i checked the "weekly challenge" checkbox when submitting it :/
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Wait, what? Okay, I wasn't aware of that. I was using the RGB codes, myself, rather than hex. Is it just smarter to use the hex codes for accuracy?