just remove the ;

CREATE FUNCTION dbo.testFunction

(@STARTDATE datetime,@EntDt datetime)

RETURNS TABLE

AS

RETURN

with DateList as

(

select cast(@STARTDATE as datetime) DateValue

union all

select DateValue + 1 from DateList

where DateValue + 1 < convert(VARCHAR(15),@EntDt,101)

)select * from DateList where DATENAME(WEEKDAY, DateValue ) not IN ( 'Saturday','Sunday' )

GO

Let me know if this works