so you try to reference to a list of six thumbs in a single href?
then i would have expected a for-statement to be honest.
I'm not sure what you are trying to print here,
<?php print $node->field_video_video['filename'] ?>
but what does this single line show if you would put this PHP in the body of your page? this can quite likely help you or atleast us also in debugging, right now we have no idea what output this will give.
also, your php is missing a semicolon in the end which can muck up it's execution, though not always (so that's a gamble there).
is the definition $node->field_video_video['filename'] a single variable? else you will need to use a comma between. (i.e. $node->field_video_video,['filename'] ) side note: i am horrible with any type of array as of yet, so i may be judging this wrongly.