[imp] sendmail is not a valid file

[mbneto]

Hi,

I'd like to enable safe mode in my current setup but it seems that I am
doing something wrong.

I can access my messages but when I try to send a new one I get error
message in my horde.log

Jul 12 15:00:44 HORDE [error] [imp] sendmail [/var/www/phpexecdir/sendmail]
is not a valid file [on line 1042 of "/var/www/html/horde/imp/compose.php"]

My webserver configuration

<Directory /var/www/html/horde/>
               php_admin_flag safe_mode On
               php_admin_value upload_tmp_dir "/var/www/html/horde/tmp"
               php_admin_value safe_mode_include_dir
"/usr/share/pear:/var/www/html/horde/"
               php_admin_value open_basedir
".:/usr/share/pear:/var/www/html/horde/"
               php_admin_value safe_mode_exec_dir
"/var/www/phpexecdir/"
</Directory>

I have copied sendmail from it's original location to this new one.

Any tips?