label element is not a known element
<p>i change my asp website to ajax enabled website. in my page .cs files for the elements like  labels,dropdownlist, gridview says element is not a known element. </p>

<p>i am currently using visual studio 2005 version. i used it by first put the "scriptmanager" from ajax tool box and put a update panel and put my masterpage into the updatepanel. </p>
