The <NOFRAMES> element is not present or it does not contain a link to an alternative version of the page.

A valid NOFRAMES section should exist within the outer FRAMESET section.
Remember that a NOFRAMES section is valid if it:

• contains at least one word of text or accessible HTML code;
• provides the necessary links to navigate the site;
• does not tell the users that they should upgrade to a browser that supports frames.

A NOFRAMES element that does not contain links prevents the reader from accessing the same navigation options offered to those with frames-enabled browsers.

Consider adding the following HTML code before the last </FRAMESET> tag in the document:

     <NOFRAMES>
     <P>Here is the <A href="main-noframes.html">
              non-frame based version of the document.</A></P>
     </NOFRAMES>

Without specifying a <NOFRAMES> element, the site may appear as a blank page to users with browsers unable to handle frames, such as early versions of popular browsers and current special-purpose browsers like voice-enabled computers and browsers for PDAs.

The <NOFRAMES> element should be used to provide users of browsers unable to handle frames an alternative way to access the site, possibly with degraded graphic and interaction quality.
For example, a <NOFRAMES> element containing text stating that the page cannot be displayed by the browser being used does not help users access the page.