Try not to separate the message tag and CDATA portion. Tthe parser might creates a text node enclosing the CDATA one if it sees any space, and xwork just reads the first node (therefore, an empty text). Example:-
<field name="password"> <field-validator type="requiredstring"> <message><![CDATA[ Debe proporcionar una contraseña para el usuario. ]]></message> </field-validator> </field>
Note: there's no spacing in the following line
<message><![CDATA[ ...]]></message>
Contributor: Ruben