Sorry for such a long delay in replying!

And now that I've had time to really look at this problem, I realized that I was looking in the totally wrong direction for helping you and for that I apologize! It's actually a really simple fix! You're missing a closing bracket in your code.

Your code:
<?php $result = $database->query("SELECT * FROM `collecting` WHERE `tcg`='$id' AND `mastered` = '1' ORDER BY `mastereddate`"); while ( $row = mysql_fetch_assoc($result) ) { echo '<a href="mastered.php?id='.$id.'&deck='.$row['id'].'"><img src="'.$tcginfo['cardsurl'].''.$row['badge'].'" alt="'.$row['deck'].'" title="'.$row['deck'].': Mastered '.$row['mastereddate'].'" /></a> '; ?>

What your code should look like:
<?php $result = $database->query("SELECT * FROM `collecting` WHERE `tcg`='$id' AND `mastered` = '1' ORDER BY `mastereddate`"); while ( $row = mysql_fetch_assoc($result) ) { echo '<a href="mastered.php?id='.$id.'&deck='.$row['id'].'"><img src="'.$tcginfo['cardsurl'].''.$row['badge'].'" alt="'.$row['deck'].'" title="'.$row['deck'].': Mastered '.$row['mastereddate'].'" /></a> '; } ?>

There should be a } right before the ending ?>! That's what's breaking everything else in it.