I have this code, but <h:commandButton> don´t works, anyone knows why?

<rich:modalPanel id="panel" width="750" height="300">

 <f:facet name="header">
 <h:panelGroup>
 <h:outputText value="Dados"></h:outputText>
 </h:panelGroup>
 </f:facet>
 <f:facet name="controls">
 <h:panelGroup>
 <h:graphicImage value="/close.png" style="cursor:pointer" id="hidelink"/>
 <rich:componentControl for="panel" attachTo="hidelink" operation="hide" event="onclick"/>
 </h:panelGroup>
 </f:facet>
 <table id="mainDataTable">
 <tr>
 <td> <h:outputText value="Confira os dados: " style="font-style: italic; font-size: 1.5em"/> </td> </tr><br/>
 <br/>
 <tr>
 <td> <h:outputText value="Nome:" style="font-style: italic"/></td>
 <td> <h:outputText id="textnome" value="#{ususario.nome}"/> </td></tr>
 <tr>
 <td> Sobrenome</td>
 <td> <h:outputText id="textsobrenome" value="#{ususario.sobrenome}"/> </td></tr>
 <tr>
 <td> CPF </td>
 <td><h:outputText id="textcpf" value="#{ususario.cpf}"/></td></tr>
 <tr>
 <td> Endereço </td>
 <td> <h:outputText id="textendereco" value="#{ususario.endereco}"/></td>
 </tr>
 <tr>
 <td> <h:commandButton id="inser" value="Inserir Dados" action="#{ususario.inserir}" /> </td>

 <td> </td>
 </tr>

 </table>
 </rich:modalPanel>