Hi Pasha,
I used the same code you added to Muse page with my page source:
<iframe name="gs3" src="http://dhell.businesscatalyst.com/laptops/toshiba" width="1024" height="800” frameborder="0" scrolling=“no” seamless></iframe>
and it worked.
You might need to check the page code, seems the page has no data on it. When I added your code, on previewing the page I get an empty page.
Regards,
Gaurav Aggarwal