diff --git a/apps/app_voicemail.c b/apps/app_voicemail.c
index 96461fce9a..b5897df554 100644
--- a/apps/app_voicemail.c
+++ b/apps/app_voicemail.c
@@ -619,9 +619,9 @@ static struct ast_flags globalflags = {0};
 
 static int saydurationminfo;
 
-static char dialcontext[AST_MAX_CONTEXT];
-static char callcontext[AST_MAX_CONTEXT];
-static char exitcontext[AST_MAX_CONTEXT];
+static char dialcontext[AST_MAX_CONTEXT] = "";
+static char callcontext[AST_MAX_CONTEXT] = "";
+static char exitcontext[AST_MAX_CONTEXT] = "";
 
 static char cidinternalcontexts[MAX_NUM_CID_CONTEXTS][64];
 
@@ -665,12 +665,9 @@ static void populate_defaults(struct ast_vm_user *vmu)
 	ast_copy_flags(vmu, (&globalflags), AST_FLAGS_ALL);	
 	if (saydurationminfo)
 		vmu->saydurationm = saydurationminfo;
-	if (callcontext)
-		ast_copy_string(vmu->callback, callcontext, sizeof(vmu->callback));
-	if (dialcontext)
-		ast_copy_string(vmu->dialout, dialcontext, sizeof(vmu->dialout));
-	if (exitcontext)
-		ast_copy_string(vmu->exit, exitcontext, sizeof(vmu->exit));
+	ast_copy_string(vmu->callback, callcontext, sizeof(vmu->callback));
+	ast_copy_string(vmu->dialout, dialcontext, sizeof(vmu->dialout));
+	ast_copy_string(vmu->exit, exitcontext, sizeof(vmu->exit));
 	if (vmmaxsecs)
 		vmu->maxsecs = vmmaxsecs;
 	if (maxmsg)
diff --git a/channels/chan_agent.c b/channels/chan_agent.c
index cda841fa51..d1231556e8 100644
--- a/channels/chan_agent.c
+++ b/channels/chan_agent.c
@@ -390,10 +390,10 @@ static int __agent_start_monitoring(struct ast_channel *ast, struct agent_pvt *p
 		/* substitute . for - */
 		if ((pointer = strchr(filename, '.')))
 			*pointer = '-';
-		snprintf(tmp, sizeof(tmp), "%s%s",savecallsin ? savecallsin : "", filename);
+		snprintf(tmp, sizeof(tmp), "%s%s", savecallsin, filename);
 		ast_monitor_start(ast, recordformat, tmp, needlock, X_REC_IN | X_REC_OUT);
 		ast_monitor_setjoinfiles(ast, 1);
-		snprintf(tmp2, sizeof(tmp2), "%s%s.%s", urlprefix ? urlprefix : "", filename, recordformatext);
+		snprintf(tmp2, sizeof(tmp2), "%s%s.%s", urlprefix, filename, recordformatext);
 #if 0
 		ast_verbose("name is %s, link is %s\n",tmp, tmp2);
 #endif
diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index b22d798ff4..2f5c5c5c2f 100644
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -4948,7 +4948,7 @@ static int sip_register(char *value, int lineno)
 	regobjs++;
 	ASTOBJ_INIT(reg);
 	ast_string_field_set(reg, callback, callback);
-	if (username)
+	if (!ast_strlen_zero(username))
 		ast_string_field_set(reg, username, username);
 	if (hostname)
 		ast_string_field_set(reg, hostname, hostname);
diff --git a/pbx/pbx_realtime.c b/pbx/pbx_realtime.c
index 9ee770c99a..d1011fe8eb 100644
--- a/pbx/pbx_realtime.c
+++ b/pbx/pbx_realtime.c
@@ -211,7 +211,7 @@ static int realtime_exec(struct ast_channel *chan, const char *context, const ch
 							  "Application: %s\r\n"
 							  "AppData: %s\r\n"
 							  "Uniqueid: %s\r\n",
-							  chan->name, chan->context, chan->exten, chan->priority, app, appdata ? appdata : "(NULL)", chan->uniqueid);
+							  chan->name, chan->context, chan->exten, chan->priority, app, !ast_strlen_zero(appdata) ? appdata : "(NULL)", chan->uniqueid);
 				
 				res = pbx_exec(chan, a, appdata);
 			} else