IFrame disappears in IE (.Net 1.1)

[Guest]

I have two aspx pages. First one, page1.aspx, has an iframe inside. Src
attribute of this iframe is pointing to the second page, page2.aspx. In
page2.aspx I have a textbox and a dropdownlist. Autoposkback attribute for
both the textbox and dropdownlist is set to true.

When I open page1.aspx inside Internet Explorer (Ver 6.0) I can see the
textbox and dropdown. Now if I enter something inside the textbox and click
on the dropdown, iframe disappears (if I tab away or click any where else on
the screen it will work). This page works fine in FireFox (also I tried the
same thing in .Net 2.0 and it works fine).

Is there something I can do to make this work in .Net 1.1 and IE?

Thanks,
Edge