Hello.
You do not need to have some special web part for this purpose on your master page or content page, it should be added automatically into one particular
literal control.
When you see source code (rendered html code) of your page, can you see following tags within?
<meta name="description" ... />
<meta name="keywords" ... />
Could you please whether your physical master page contains this control?
<asp:literal runat="server" id="ltlTags" enableviewstate="false" />
Best Regards,
Radek Macaik