[horde] PHP errors in horde logs

["Lic. Cristóbal Sabroe Yde"]

Why am I getting all kinds of PHP errors in my horde.log file?
Can anybody help me to eliminate these?

2013-05-14T17:01:44-03:00 NOTICE: HORDE [imp] PHP ERROR: Undefined 
index: download [pid 12415 on line 83 of 
"/srv/www/htdocs/HGWE-2013/imp/templates/dynamic/message.html.php"]
2013-05-14T17:01:44-03:00 NOTICE: HORDE [imp] PHP ERROR: Undefined 
index: download [pid 12415 on line 83 of 
"/srv/www/htdocs/HGWE-2013/imp/templates/dynamic/message.html.php"]
2013-05-14T17:01:44-03:00 NOTICE: HORDE [imp] PHP ERROR: Undefined 
index: link_all_attachments [pid 11157 on line 994 of 
"/srv/www/htdocs/HGWE-2013/imp/compose.php"]

My Horde conf.php:
$conf['log']['priority'] = 'INFO';
$conf['log']['ident'] = 'HORDE';
$conf['log']['name'] = '/var/log/horde/hgwe-2013.log';
$conf['log']['params']['append'] = true;
$conf['log']['params']['format'] = 'default';
$conf['log']['type'] = 'file';
$conf['log']['enabled'] = true;
$conf['log_accesskeys'] = false;

Thanks
-- 
Logo UTI *Cristóbal*