Run Stored Procedure using VBA

I have a sp that creates a new table, with the new table's name to be the value of a field on the form

ALTER PROCEDURE procNewPayee
(@Payee_id as char(18))
AS
SET NOCOUNT ON
DECLARE @table_name char(20)
DECLARE @sql_string NVARCHAR(500)

SET @table_name =  CAST(@Payee_id AS varchar(18))

SET @sql_string = 'CREATE TABLE ' + @table_name + '(Catalog_ID char(24),Cur_Code char(3), Sale_Qty int, Sale_Retail float(8),Sale_Period int ,Contract_Royalty float(2),Royalty_Payable float(2))'

EXEC sp_executesql @sql_string

I try to run it from my form

Dim PayeeID As String
PayeeID = Me.Payee_ID
DoCmd.RunSQL "EXEC procNewPayee 'WHERE @Payee_ID = PayeeID'"

I get the error

Incorrect syntax near the keyword 'WHERE'

(1) How can I fix this?
(2) How can I prevent this running if a table with that name already exists?

Thanks, Doozy