Don't specify a table name or alias for the columns you're updating.
You also can't refer to columns in a sub-query from the outer query. You need to join to the relevant tables instead.
UPDATE
m
SET
rohsstatus = RHst.Name
FROM
#Manufacture m
INNER JOIN Parts.ROHS Rhh ON Rhh.zpartid = m.partid
INNER JOIN Nop_AcceptedValuesOption RHst ON RHst.AcceptedValuesOptionID = Rhh.RoHSStatus AND RHst.AcceptedValuesID = 911
;