Index: includes/replies/functions.php
===================================================================
--- includes/replies/functions.php	(revision 6239)
+++ includes/replies/functions.php	(working copy)
@@ -437,7 +437,7 @@
 			if ( bbp_is_topic_trash( $topic_id ) ) {
 
 				// Get pre_trashed_replies for topic
-				$pre_trashed_replies = get_post_meta( $topic_id, '_bbp_pre_trashed_replies', true );
+				$pre_trashed_replies = (array) get_post_meta( $topic_id, '_bbp_pre_trashed_replies', true );
 
 				// Add this reply to the end of the existing replies
 				$pre_trashed_replies[] = $reply_id;
@@ -456,7 +456,7 @@
 			if ( bbp_is_topic_spam( $topic_id ) ) {
 
 				// Get pre_spammed_replies for topic
-				$pre_spammed_replies = get_post_meta( $topic_id, '_bbp_pre_spammed_replies', true );
+				$pre_spammed_replies = (array) get_post_meta( $topic_id, '_bbp_pre_spammed_replies', true );
 
 				// Add this reply to the end of the existing replies
 				$pre_spammed_replies[] = $reply_id;