How to Recursively Sum a Sum?

Sorry, everyone, this is driving me nuts.  I have the following query, which gives me the relative percentage of [INDEX MARKET CAP].

SELECT *, [INDEX MARKET CAP] * 100/SUM([INDEX MARKET CAP]) OVER() as [%]
FROM [S&P_Emerging_SmallCap_(US_Dollar)]

So, I get a sum of the [INDEX MARKET CAP], and then find the relative percentage of each items in the INDEX MARKET CAP.  Great!  now, I'm trying to modify the query a bit to give me the SUM of each relative INDEX MARKET CAP.  So, the sum will be 100%!  I just want to prove that the query works.

I'm trying to follow the example here.

http://technet.microsoft.com/en-us/library/ms190766%28v=sql.105%29.aspx

It seems so simple, but this dang thing just won't work.

I think it should be something like this.

;With CTE (Company, [%])
AS
SELECT *, [INDEX MARKET CAP] * 100/SUM([INDEX MARKET CAP]) OVER() as [%]
FROM [S&P_Emerging_SmallCap_(US_Dollar)] 
Select Company, SUM([%]) as Total
FROM CTE
Group By Company, Total

I keep getting this.

Msg 156, Level 15, State 1, Line 3
Incorrect syntax near the keyword 'SELECT'.

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