Formattering af dato

Følgende stump af en Stored Procedure kørte fint under SQL Server 2000, men fejler under SQL Server 2005! :(

UPDATE [myTabel] SET Year = RIGHT('0000' + CONVERT(varchar(4), DATEPART(year,[date])),4)
UPDATE [myTabel] SET MONTH = RIGHT('00' + CONVERT(varchar(2), DATEPART(month, [date]) ), 2)
UPDATE [myTabel] SET WEEK = RIGHT('00' + CONVERT(varchar(2), master.dbo.ISOweek([date]) ), 2)

Fejlen der vises i loggen:

Message
Executed as user: Domain\myLogin. Cannot find either column "master" or the user-defined function or aggregate "master.dbo.ISOweek", or the name is ambiguous. [SQLSTATE 42000] (Error 4121).  The step failed.