Make sure the references to the page are relative and do not include the full URL. Using the node reference is best in the event that the page name changes (and therefore the URL).
<map name=”m_exhibitionmain” id=”m_exhibitionmain”>
<area shape=”circle” coords=”87,258, 19” href=”/node/23” alt=”” />
<area shape=”circle” coords=”56,58, 20” href=”/node/21” title=”Wadi Natrun Exibition” alt=”Wadi Natrun Exibition” />
</map>