Visual Studio 2008 Won't show Split or Design View

[Nathan Sokalski]

Whenever I try to use Split or Design View for an ASP.NET Page that uses a
Master Page in Visual Studio 2008 I recieve the following error:

Master Page error
The page has one or more <asp:Content> controls that do not correspond with
<asp:ContentPlaceHolder> controls in the Master Page.
Correct the problem in Code View:
<the ID(s) of my Content controls>

This is happening in all of my Web Applications, and yes, I did check the
code, and all the Content and ContentPlaceHolder controls are correct (I
have even compiled the code and used it, and it looks and does exactly what
I want and expect). Why am I recieving this error about all my content
pages? Thanks.