Related article script not working 100%

Hi there.

I tried to modify a related article script from tags to categories. Now it seemed to work except that it kind of generates random suggestions that are not even from the same category.

<div class="relatedposts">
					  <h2>Related posts</h2>
					<?php
						$orig_post = $post;
						global $post;
						$categories = get_the_category($post->ID);

						if ($categories) {
							$category_ids = array();
						foreach($categories as $individual_category) $category_ids[] = $individual_category->term_id;
							$args=array(
								'category__in' => $category_ids,
								'post__not_in' => array($post->ID),
								'posts_per_page'=>3, // Number of related posts to display.
								'caller_get_posts'=>1,
								'orderby'=>'rand' //Random
							);

						$my_query = new wp_query( $args );

						while( $my_query->have_posts() ) {
							$my_query->the_post();
						?>

						<div class="relatedthumb">
							<a rel="external" href="<? the_permalink()?>"><?php the_post_thumbnail(array(287,208)); ?><br />
							<?php the_title(); ?>
							</a>
						</div>

						<?php }
						}
						$post = $orig_post;
						wp_reset_query();
						?>
					</div>

Any suggestions where I went wrong?

regards