Framesets

I'm trying to compile a document that contains a frameset, like this:

        <frameset rows="*" cols="300, *" frameborder="yes" border="1" 
bordercolor="#000000">
                <frameset rows="50%, 50%" cols="*" frameborder="yes" border="1" 
bordercolor="#000000">
                        <frame name="sites" src="sites.html"/>
                        <frame name="items" src="items.html"/>
                </frameset>
                <frame name="maindisplay" src="main.html"/>
        </frameset>

When I stream the compiled class to the browser, I get this:

        <frameset rows="*" cols="300, *" frameborder="yes" border="1" 
bordercolor="#000000">
                <frameset rows="50%, 50%" cols="*" frameborder="yes" border="1" 
bordercolor="#000000">
                        <frame name="sites" src="sites.html"/>
                        <frame name="items" src="items.html"/>
                        <frame name="maindisplay" src="main.html"/>
                </frameset>
        </frameset>

Of course, putting the third frame inside the first frameset isn't what I want. 
Is there any way to get around this?