Error after selecting an option from selectManyListbox

I'am using JSF2.0/primefaces,

I have an error that I can not understand it's cause, I have 2 components selectOneMenu and selectManyListbox ,when I choose an option from the first the second is filled ,the problem is when I choose an option from the second the following error appear:

 f1:env1 : erreur de validation. La valeur est incorrecte

JSF :

      <h:outputLabel value="Platform:" /> 
          <h:selectOneMenu value="#{FMTools.platform}" id="platforms">
           <f:selectItem itemLabel="-- Select Plateform-- " itemValue="0"/> 
           <f:selectItems value="#{FMTools.getMyListPaltform()}" />
           <f:ajax listener="#{FMTools.UpdateChangeEnvironment()}" render="env1" />
       </h:selectOneMenu>


     <h:selectManyListbox   value="#{FMTools.s开发者_如何转开发electedEnvironment}"  id="env1" size="3">
         <f:selectItem itemLabel="-- Select Environment -- " itemValue="0"/> 
         <f:selectItems value="#{FMTools.getMyListEnvironment()}" />
     </h:selectManyListbox>   //when I choose an environment the error appear

My BEAN:

private List<SelectItem> MyListEnv;
private ArrayList<String> selectedEnvironment;


public List<SelectItem> getMyListEnvironment()
 {
   if (MyListEnv == null) {
    MyListEnv = new ArrayList<SelectItem>();
    for (String val : this.getMyListEnvironmentByPlatform()) {
    MyListEnv.add(new SelectItem(val));
    }
  }
     return MyListEnv;
 }