Can't open a jsp in a pop up or iframe from another jsp in the same struts portlet

[Jeera Kamar]

Hi There,
I have a simple struts portlet "MNPPortlet" deployed in weblogic portal, it contains some JSPs as the below hirearchy

MNPPortlet
WebContent
pages
A.jsp
B.jsp

I just want to open B.jsp in a popup window or in an iframe from A.jsp, I have tried the following
1- window.open("B.jsp")
2- <IFRAME src="B.jsp">

but it doesn't seem to work, I always get 404 page not found error, since it generates wrong URLs, any ideas how can i get the right URIs generated ?
P.S. it's working fine as struts application, not portlet

Thanks alot