HTML 4.0 Problems using Netscape as Browser

Hi, I make my first steps in programming ASP.NET-Apps.
While writing, testing and excuting the Application I always use the
built-in IE6.0 - everthing ok - no probs - no error.
Then I tested my Web-Application with Netscape and got display-problems:
"HTML frameset displays multiple Web pages. To view this frameset, use a Web
browser that supports HTML 4.0 and later."
I snooped through the internet and found a setting for the IIS or the APP.
So I changed machine.config-file and th Web.config -file of the APP.
But it didn't work.
Do you know the right setting for actual Webbrowsers. I would like to set
the machine.config -file.
Greeting and tnx in advance> Then I tested my Web-Application with Netscape and got display-problems:
> "HTML frameset displays multiple Web pages. To view this frameset, use a
Web
> browser that supports HTML 4.0 and later."
What version of Netscape are you using? Netscaps has supported framesets
since version 2, IIRC.
-Darrel