diff --git a/sc2/ChangeLog b/sc2/ChangeLog
index 52d8aa10e..e5e330365 100644
--- a/sc2/ChangeLog
+++ b/sc2/ChangeLog
@@ -1,4 +1,6 @@
 Changes towards version 0.4:
+- Fixed crash in conversation summary and ffw/frew problem when
+  selling data to Melnorme (bug #476), from chmmravatar
 - Flush input after selecting "Navigate" (bug #475) - Michael
 - Fixed ships in solar system getting displaced after having
   visited a planet (bug #365) -Alex
diff --git a/sc2/src/sc2code/comm.c b/sc2/src/sc2code/comm.c
index f0a8089d1..bf1b6b0fb 100644
--- a/sc2/src/sc2code/comm.c
+++ b/sc2/src/sc2code/comm.c
@@ -1704,6 +1704,8 @@ DoCommunication (PENCOUNTER_STATE pES)
 			for (curr = first_chain; curr != NULL; curr = curr->next)
 			{
 				temp = curr->tag.data;
+				if (temp == NULL)
+					break;
 				// fprintf (stderr, "%s\n", temp);
 				while (wstrlen (temp) > (unsigned int) SUMMARY_CHARS
 						&& !(GLOBAL (CurrentActivity) & CHECK_ABORT))
diff --git a/sc2/src/sc2code/libs/sound/sound.c b/sc2/src/sc2code/libs/sound/sound.c
index ba2266c74..52a8e2a6b 100644
--- a/sc2/src/sc2code/libs/sound/sound.c
+++ b/sc2/src/sc2code/libs/sound/sound.c
@@ -152,7 +152,7 @@ get_previous_chain (TFB_SoundChain *first_chain, TFB_SoundChain *current_chain)
 		return (prev_chain);
 	while (prev_chain->next)
 	{
-		if (prev_chain->next == current_chain)
+		if (prev_chain->next == current_chain || !prev_chain->next->tag.data)
 			return (prev_chain);
 		prev_chain = prev_chain->next;
 	}
diff --git a/sc2/src/sc2code/libs/sound/trackplayer.c b/sc2/src/sc2code/libs/sound/trackplayer.c
index fa3792da5..b2183e240 100644
--- a/sc2/src/sc2code/libs/sound/trackplayer.c
+++ b/sc2/src/sc2code/libs/sound/trackplayer.c
@@ -669,7 +669,7 @@ FastForward_Page ()
 	{
 		TFB_SoundChain *cur_ptr = sound_sample->play_chain_ptr;
 		LockMutex (soundSource[SPEECH_SOURCE].stream_mutex);
-		while (cur_ptr->next && ! cur_ptr->tag.type)
+		while (cur_ptr->next && ! cur_ptr->next->tag.type)
 			cur_ptr = cur_ptr->next;
 		if (cur_ptr->next)
 		{