Ok, I am new to WordPress, so maybe I am missing something. (This has little relevance to your problem, just noticing it) Why is PHP processing terminated after virtually every line, even if more PHP directly follows it? Seems rather pointless and even possibly detrimental to load times.
Ok, on to your problem. As stated above, I am new to WordPress, and have not seen the PHP behind some of the functions including the_tags(), the_post(), etc.. Could you please provide this?
I do not see the variable $post being called anywhere, but are you able to find when it is used? Just taking a guess, but since it is set to the first record of the array $posts (the first post perhaps?), it may be the source of your problem.
