You write SET only once in update clause:

WITH UpdateAverageLabourCost (ProductId,OH,Labour) AS

(

SELECT

AC.ProductId,

AC.OH,

AC.AVGDirectLabour + MAN + SUB - OH AS Labour

FROM dbo.AVGCost AC

INNER JOIN dbo.Products p ON AC.ProductId = p.CrossReference

WHERE Type <> 'P' AND AVGDirectLabour >0

)

UPDATE dbo.Products

SET Products.SLC = Labour,

Products.SOC = OH

FROM

UpdateAverageLabourCost

WHERE Products.CrossReference = UpdateAverageLabourCost.ProductId

Regards

Piotr