Hi Sara,
input field must have a attribute value.
THis is one example from same view
<thtmlb:inputField id = "fromAddress"
value = "<%= gv_from %>"
width = "100%"
disabled = "true" />
In this case gv_form is your page attribute, and you can set this from set_models method of your controller.
You can also choose to add a public attribute in controller and access the attribute like
<%= controller->zttr %> .
Hope this helps.
Regards
Anirudha