Wordpress post->ID Problem - php

Question

This is a wordpress question. I am trying to use a bit of code that works just fine on my home page on my inner page templates:
query_posts('cat=4');
// The Loop
echo '<div id="cal_details"><ul>';
while ( have_posts() ) : the_post();
$cal_date_j = date('j', intval(get_post_meta($post->ID, 'date_value', true)));
$cal_date_n = date('n', intval(get_post_meta($post->ID, 'date_value', true)));
$my_array[] = date('j, n', intval(get_post_meta($post->ID, 'date_value', true)));
$issetdate = get_post_meta($post->ID, 'date_value', true);
if (isset($issetdate)) {
echo '<li class="cal_event_li list_item_' . $cal_date_j . '_' . $cal_date_n . '">';
echo '<a href="' . get_permalink() . '">';
the_title();
echo '</a></li>';
}
endwhile;
echo '</ul></div>';
However, this doesn't seem to work on the inner-pages. All the titles links are being outputted correctly but it won't print the get_post_meta part correctly.
The list items all display something like <li class="cal_event_li list_item_1_1">
I think there is perhaps some issue with the way I have tried to use $post->ID but Im not sure whats going on here. Any ideas?

Answer 1

When you use query_posts you have to call global $post to get the post_meta. If you're only calling one category why don't you just use an archive template?
Also if you're going to use query_posts make sure you reset the query afterwords so plugins, sidebars, etc can still interact with the loop for conditionals etc..
global %post;
query_posts('cat=4');
// The Loop
//more stuff
endwhile;
wp_reset_query();

Answer 2

try replacing $post->ID with the_ID() in the inner pages. something like this
query_posts('cat=4');
// The Loop
echo '<div id="cal_details"><ul>';
while ( have_posts() ) : the_post();
$cal_date_j = date('j', intval(get_post_meta(the_ID(), 'date_value', true)));
$cal_date_n = date('n', intval(get_post_meta(the_ID(), 'date_value', true)));
$my_array[] = date('j, n', intval(get_post_meta(the_ID(), 'date_value', true)));
$issetdate = get_post_meta(the_id(), 'date_value', true);
if (isset($issetdate)) {
echo '<li class="cal_event_li list_item_' . $cal_date_j . '_' . $cal_date_n . '">';
echo '<a href="' . get_permalink() . '">';
the_title();
echo '</a></li>';
}
endwhile;
echo '</ul></div>';