if ( in_category('fruit') ) {
    include 'single-fruit.php';
} elseif ( in_category('vegetables') ) {
    include 'single-vegetables.php';
} else {
    // Continue with normal Loop
    if ( have_posts() ) : while ( have_posts() ) : the_post();
    // ...
}

if ( in_category( 'pachyderms' )) {
    // They have long trunks...
} elseif ( in_category( array( 'Tropical Birds', 'small-mammals' ) )) {
    // They are warm-blooded...
} else {
    // etc.
}

The unnecessary semi-colon is probably causing the error. <?php } else { ;?> should be <?php } else { ?>. Try this:

<?php if (in_category( array(6,14,15,13) )) { ?>
<div id="eatheader">

<?php } elseif (in_category( array(7,11,12,10,9) )) { ?>
<div id="goheader">

<?php } elseif (in_category( array(4,16,17,18,19) )) { ?>
<div id="playheader">

<?php } elseif (in_category( array(3,22,21,26) )) { ?>
<div id="shopheader">

<?php } elseif (in_category(5)) { ?>
<div id="talkheader">

<?php } else { ?>
<div id="defaultheader">

<?php } ?>