Sergey,

See my question inline

>See corrections inline.
>>

>>/*
>>   If exists, grab CartID and update LastModified field
>>   otherwise insert a record and grab generated CartID
>>*/
>>/* The code bellow belongs to Bob Archer
>>
>>-- Code from Mike Levy
>
>DECLARE @ErrCode
>SET @ErrCode = 0
>
>>IF EXISTS (SELECT CartID FROM cart WHERE UserID = @tcUserID)

?? Should be BEGIN
>>   UPDATE cart
>>   SET LastModTs = CURRENT_TIMESTAMP,
>>   @CartID = CartID
>>   FROM cart
>>   WHERE UserID = @tcUserID
>    SET @ErrCode = @@ERROR
 ?? Should be END (otherwise SET @ErrCode would be executed regardless of IF condition)

>>ELSE
>>        BEGIN
>>	   INSERT INTO cart (UserID) values (@tcUserID)
>           SET @ErrCode = @@ERROR
>>
>>	   SELECT @CartID = SCOPE_IDENTITY()
>>        END
>>
>>     IF @ErrorCode <> 0   -- CNG
>>        BEGIN
>>            ROLLBACK TRAN
>>            PRINT 'ERROR: An error occurred while attempting to insert record to the Cart Table.'
>>            RETURN 4
>>        END

>>
>>Basically, I want to check, if my insert was correct or my update was correct. In both cases, if something got wrong, I need to rollback and get out from procedure.