diff --git a/apps/conference/Conference.cpp b/apps/conference/Conference.cpp
index 31554b1f..4c3de52a 100644
--- a/apps/conference/Conference.cpp
+++ b/apps/conference/Conference.cpp
@@ -2,6 +2,7 @@
  * $Id$
  *
  * Copyright (C) 2002-2003 Fhg Fokus
+ * Copyright (C) 2007 Juha Heinanen (USE_MYSQL parts)
  *
  * This file is part of sems, a free SIP media server.
  *
@@ -74,11 +75,11 @@ int get_audio_file(string message, string domain, string language,
     if (language.empty()) {
 	if (domain.empty()) {
 	    *audio_file = string("/tmp/") + APP_NAME + "_" + message + ".wav";
-	    query_string = "select audio from " + string(DEFAULT_AUDIO_TABLE) + " where application='" + APP_NAME + "' and message='" + message + "' and language is null";
+	    query_string = "select audio from " + string(DEFAULT_AUDIO_TABLE) + " where application='" + APP_NAME + "' and message='" + message + "' and language=''";
 	} else {
 	    *audio_file = "/tmp/" + domain + "_" + APP_NAME + "_" + 
 		message + ".wav";
-	    query_string = "select audio from " + string(DOMAIN_AUDIO_TABLE) + " where application='" + APP_NAME + "' and message='" + message + "' and domain='" + domain + "' and language is null";
+	    query_string = "select audio from " + string(DOMAIN_AUDIO_TABLE) + " where application='" + APP_NAME + "' and message='" + message + "' and domain='" + domain + "' and language=''";
 	}
     } else {
 	if (domain.empty()) {
diff --git a/apps/voicemail/AnswerMachine.cpp b/apps/voicemail/AnswerMachine.cpp
index 9376ff29..1ee7f757 100644
--- a/apps/voicemail/AnswerMachine.cpp
+++ b/apps/voicemail/AnswerMachine.cpp
@@ -93,11 +93,11 @@ int get_audio_file(string message, string domain, string user,
 	    if (domain.empty()) {
 		*audio_file = string("/tmp/") + MOD_NAME + "_" + message +
 		    ".wav";
-		query_string = "select audio from " + string(DEFAULT_AUDIO_TABLE) + " where application='" + MOD_NAME + "' and message='" + message + "' and language is null";
+		query_string = "select audio from " + string(DEFAULT_AUDIO_TABLE) + " where application='" + MOD_NAME + "' and message='" + message + "' and language=''";
 	    } else {
 		*audio_file = string("/tmp/") + domain + "_" + MOD_NAME +
 		    "_" + message + ".wav";
-		query_string = "select audio from " + string(DOMAIN_AUDIO_TABLE) + " where application='" + MOD_NAME + "' and message='" + message + "' and domain='" + domain + "' and language is null";
+		query_string = "select audio from " + string(DOMAIN_AUDIO_TABLE) + " where application='" + MOD_NAME + "' and message='" + message + "' and domain='" + domain + "' and language=''";
 	    }
 	} else {
 	    if (domain.empty()) {
@@ -175,7 +175,7 @@ int AnswerMachineFactory::loadEmailTemplatesFromMySQL()
 	    unsigned long length = row["template"].size();
 	    string tmp_file, tmpl_name;
 	    row = res.at(i);
-	    if (string(row["language"]) == "NULL") {
+	    if (string(row["language"]) == "") {
 		tmp_file = "/tmp/voicemail_email.template";
 		tmpl_name = DEFAULT_MAIL_TMPL;
 	    } else {
@@ -217,7 +217,7 @@ int AnswerMachineFactory::loadEmailTemplatesFromMySQL()
 	    unsigned long length = row["template"].size();
 	    string tmp_file, tmpl_name;
 	    row = res.at(i);
-	    if (string(row["language"]) == "NULL") {
+	    if (string(row["language"]) == "") {
 		tmp_file = "/tmp/" + string(row["domain"]) +
 		    "_voicemail_email.template";
 		tmpl_name = string(row["domain"]);
diff --git a/doc/Readme.conference b/doc/Readme.conference
index 83389ec7..ac74456f 100644
--- a/doc/Readme.conference
+++ b/doc/Readme.conference
@@ -73,7 +73,7 @@ CREATE TABLE default_audio (
   id int(10) unsigned NOT NULL auto_increment,
   application varchar(32) NOT NULL,
   message varchar(32) NOT NULL,
-  `language` char(2) default NULL,
+  `language` char(2) NOT NULL default '',
   audio mediumblob NOT NULL,
   PRIMARY KEY  (id),
   UNIQUE KEY application (application,message,`language`)
@@ -84,7 +84,7 @@ CREATE TABLE domain_audio (
   application varchar(32) NOT NULL,
   message varchar(32) NOT NULL,
   domain varchar(128) NOT NULL,
-  `language` char(2) default NULL,
+  `language` char(2) NOT NULL default '',
   audio mediumblob NOT NULL,
   PRIMARY KEY  (id),
   UNIQUE KEY application (application,message,domain,`language`)
@@ -92,7 +92,8 @@ CREATE TABLE domain_audio (
 
 The first one stores default audio files and the latter domain specific
 audio files.  Application value must be 'conference' and message values
-are 'first_participant_msg', 'join_snd', and 'drop_snd'.
+are 'first_participant_msg', 'join_snd', and 'drop_snd'.  Language value
+is a two letter code of a language or '' if language is unknown.
 
 When an audio file is fetched from database, it is stored in /tmp
 directory.
diff --git a/doc/Readme.voicemail b/doc/Readme.voicemail
index 98846a7f..d01da0cd 100644
--- a/doc/Readme.voicemail
+++ b/doc/Readme.voicemail
@@ -127,7 +127,7 @@ CREATE TABLE domain_template (
   application varchar(32) NOT NULL,
   message varchar(32) NOT NULL,
   domain varchar(128) NOT NULL,
-  `language` char(2) default NULL,
+  `language` char(2) NOT NULL default '',
   template text NOT NULL,
   PRIMARY KEY  (id)
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1;
@@ -136,12 +136,14 @@ CREATE TABLE default_template (
   id int(10) unsigned NOT NULL auto_increment,
   application varchar(32) NOT NULL,
   message varchar(32) NOT NULL,
-  `language` char(2) default NULL,
+  `language` char(2) NOT NULL default '',
   template text NOT NULL,
   PRIMARY KEY  (id)
 ) ENGINE=MyISAM  DEFAULT CHARSET=latin1;
 
 Application value is 'voicemail' and message value is 'email_tmpl'.
+Language value is a two letter code of a language or '' if language is
+unknown.
 
 When an audio file is fetched from database, it is stored in /tmp
 directory.