Thanks for your reply. I did not check the check box "disable javascript and external interface". I tried it locally without encryption and still it does not work. I mean it does not open new window. Here is my local xml script that I test.
<krpano version="1.0.8">
<include url="skin/defaultskin.xml" />
<plugin name="watermark"
url="skin/watermark.png"
keep="true"
blendmode="difference"
width="15%"
height="15%"
align="rightbottom"
onclick="openurl(http://www.krpano.com,_blank);"
/>
<view hlookat="0" vlookat="0" maxpixelzoom="1.0" />
<display details="22" />
<preview type="CUBESTRIP" url="image.tiles/preview.jpg" />
<image type="CUBE" multires="true" tilesize="579">
<level tiledimagewidth="3183" tiledimageheight="3183">
<left url="image.tiles/l3_l_%0v_%0h.jpg" />
<front url="image.tiles/l3_f_%0v_%0h.jpg" />
<right url="image.tiles/l3_r_%0v_%0h.jpg" />
<back url="image.tiles/l3_b_%0v_%0h.jpg" />
<up url="image.tiles/l3_u_%0v_%0h.jpg" />
<down url="image.tiles/l3_d_%0v_%0h.jpg" />
</level>
<level tiledimagewidth="1592" tiledimageheight="1592">
<left url="image.tiles/l2_l_%0v_%0h.jpg" />
<front url="image.tiles/l2_f_%0v_%0h.jpg" />
<right url="image.tiles/l2_r_%0v_%0h.jpg" />
<back url="image.tiles/l2_b_%0v_%0h.jpg" />
<up url="image.tiles/l2_u_%0v_%0h.jpg" />
<down url="image.tiles/l2_d_%0v_%0h.jpg" />
</level>
<level tiledimagewidth="796" tiledimageheight="796">
<left url="image.tiles/l1_l_%0v_%0h.jpg" />
<front url="image.tiles/l1_f_%0v_%0h.jpg" />
<right url="image.tiles/l1_r_%0v_%0h.jpg" />
<back url="image.tiles/l1_b_%0v_%0h.jpg" />
<up url="image.tiles/l1_u_%0v_%0h.jpg" />
<down url="image.tiles/l1_d_%0v_%0h.jpg" />
</level>
</image>
</krpano>
Thanks for all your help.