SQL printing error message with bad record code

SQL printing error message with bad record code

Working with SQL Server 2005 Creating Trigger which checks if inserting
not already exist. Having problem getting record parameter, there is the
code:
CREATE TRIGGER t_MFShiftTypeOperation ON [CAST$MFShiftTypeOperation]
FOR INSERT, UPDATE AS
IF @@ROWCOUNT=1 BEGIN
IF EXISTS (SELECT * FROM inserted AS I
JOIN CAST$MFShiftTypeOperation AS STO
ON ((I.ShiftTypeCode = STO.ShiftTypeCode AND
I.PackCode = STO.PackCode) OR
I.RegisterAppCode = STO.RegisterAppCode))
BEGIN
DECLARE @Bad_PackCode AS EmpUserCode_t
SET @Bad_PackCode = SELECT TOP(1) PackCode FROM inserted --there is error
ROLLBACK TRAN
PRINT 'Îperation with '+ @Bad_PackCode +' already exist'
END
END
when I'm trying to execute code, it throws me error message:
Msg 156, Level 15, State 1, Procedure t_MFShiftTypeOperation, Line 16
Incorrect syntax near the keyword 'SELECT'.
Can someone explain where is mistake, or suggest better solution.