Installing Ajax RC1 - ---- Element 'ScriptManager' is not a known element

[Elmo Watson]

Just switched from Beta2 to RC1 - I get this error for all the Ajax stuff
(UpdatePanel, UpdateProgress, etc) as well as many others any time I open
HTML source view on any page in the site.
The site Compiles/Builds just fine, btw

- I've tried tons of stuff found on Google, to no avail - -

help!

More on errors:
Error 1 Element 'ScriptManager' is not a known element. This can occur if
there is a compilation error in the Web site. [Filename]
Error 2 Element 'UpdateProgress' is not a known element. This can occur if
there is a compilation error in the Web site. [Filename]
Error 7 Element 'DropDownList' is not a known element. This can occur if
there is a compilation error in the Web site. [Filename]

 

[mike]

I am getting this message too - any solution yet?

Does it possibly have anything to do with the use of master pages? I
have a regular webfor within the same site that has a simple AJAX
animation on it that works fine (and the source does not show the error
on this page either)

When I try to use this code in a contentPlaceholder, it shows the error
and does not work correctly.