Content Gallery invalid XHTML

[spoddig]

My problem is the content gallery
you can see it here
This is the Url
http://validator.w3.org/check?uri=ww...lem%20remains.

bevore I had change the code I have the same error and more then 30 other errors.
I Change this
[img]<?php $key=[/img]ID, $key, true); ?>" class="full" />
[img]<?php $key=[/img]ID, $key, true); ?>" class="thumbnail" />

for this Code
[img]<?php $key=[/img]ID, $key, true); ?>" alt="<?php $key="articleimg"; echo get_post_meta($post->ID, $key, true); ?>" class="full" />

[img]<?php $key=[/img]ID, $key, true); ?>" alt="<?php $key="articleimg"; echo get_post_meta($post->ID, $key, true); ?>" class="thumbnail" />

but the last 2 errors I dont konw what can i do
Greatings from Spain

Ps sorry for my wron english