Yes, sorry, Is the DLL accessable?

Is the DDL accessible?

Is it possible someone opened and converted the project and saved it?
Try creating a new SSIS project, delete the Package.dtsx package it generates and add the existing package from the old...

Set up an SPN so Kerberos can forward your token

No, not without a modified column, and that must have a default of GetDate() or SysDateTime() or a trigger.

If you
SET OUOTED_IDENTIER OFF;
you can eliminate some of the pain.

DECLARE
     @FieldName VARCHAR(50) = '#14400#14400#14400#14400#14400#0#0#' ;
SELECT @FieldName;
SELECT
     Substring(@FieldName, 2, 5) Monday
   , Substring(@FieldName, 8, 5) Tuesday
   , Substring(@FieldName, 14, 5) Wednesday
   , Substring(@FieldName, 20, 5) Thursday
   ,...

I suggest trying to steer them towards using Reporting Services, a much better tool for sending scheduled reports.

DECLARE @i table --Unpaid
   (
      InvoiceID int
   );
INSERT @i VALUES (254425), (223352), (225854), (225685), (295568);
DECLARE @t table
   (
      file_name nvarchar(100)

Use developer edition

In SQL Server SQL there is no output clause for select. https://docs.microsoft.com/en-us/sql/t-sql/queries/select-transact-sql