ERROR: Value is not a valid option

[Srinivas V]

Hi All,
Please help me!!
I am having an issue with SelectOneMenu.

I have installed JSF 1.1.5-SNAPSHOT,Tomahawk1.1.5- SNAPSHOT and
tomahawk-sandbox-1.1.5-SNAPSHOT.

Previously i had myfaces1.1 jar
I dint have issue with selectOneMenu before.

Now when I submit the page, I am getting this jsf validation error:
*Container:"Value is not a valid option"*
for a selectOneMenu even if i select some option.

code:
<h:panelGroup rendered="#{reportsBean.renderContainerType}">
  <x:outputLabel for="containerfilter" value="#{
msgBundle.EPCMgr_ContainerLbl}:" styleClass="standard_text_bold"/>
  <f:verbatim><br/></f:verbatim>
  <h:selectOneMenu id="containerfilter" value="#{reportsBean.containerType}"
immediate="true" disabled="#{ reportsBean.optionDisabled }"
styleClass="standard_input">
   <f:selectItem itemValue="" itemLabel=" " />
   <f:selectItems value="#{reportsBean.containerTypeList }"/>
  </h:selectOneMenu>
 </h:panelGroup>

Can anybody tell me why it is happening?

regards
srinivas