Autocompleter keyName do not get posted in a form

Having:

<s:autocompleter name="stay.teacher.countryName" theme="simple"
list="

{'España','Portugal','Francia','Alemania','Holanda','Estados Unidos'}

"
dropdownHeight="200" value="%

{stay.teacher.countryName}

" />

The HTML generated is:

<select dojoType="struts:ComboBox"
id="teacherUpdateForm_stay_teacher_countryName" dropdownHeight="200"
name="stay.teacher.countryName" keyName="stay.teacher.countryNameKey"
initialValue="Francia">
<option value="España">España</option>
<option value="Portugal">Portugal</option>
<option value="Francia" selected="selected">Francia</option>
<option value="Alemania">Alemania</option>
<option value="Holanda">Holanda</option>
<option value="Estados Unidos">Estados Unidos</option>
</select>

If I submit the form containing the autocompleter, the fields posted values are:

stay.teacher.countryName: Francia
stay.teacher.countryNameKey: (empty)

However, if I select in the autocompleter the same item ('Francia' in my case):

a) A Javascript error is fired:

Permiso para obtener la propiedad HTMLDivElement.parentNode denegado
[Break on this error] throw _13||Error(_12);

(translation: permission denied to access HTMLDivElement.parentNode property)

b) The following is posted:

stay.teacher.countryName: Francia
stay.teacher.countryNameKey: Francia