IE6 blocking my ASP.NET app?

[Rob R. Ainscough]

Can anyone tell me why my ASP.NET app is being blocked by IE6 when I have
Privacy set to Medium? If I set it to Low Privacy, I have no problems.

My ASP.NET uses Forms Authentication
web.config
<authentication mode="Forms" >
<forms name="MyCookieName" loginUrl="Secure/Logon.aspx"/>
</authentication>

<location path="Secure">
<system.web>
<authorization>
<deny users = "?"/>
</authorization>
</system.web>
</location>

My ASP.NET web page is being referenced by another web site's frame. I even
purchases P3P and setup a w3c with my compact policy and added headers and
validated it -- all good. So I'm still confused why my ASP.NET app is being
blocked by IE6??

Any suggestions?

Thanks Rob.