RemoteException wrapping System.IndexOutOfRangeException: Index was outside the bounds of the array

In Level 3, Assignment No.1 the process stops at Assign TransactionID. with an error ‘Assign TransactionID: Index was outside the bounds of the array.’
I have attached the workflow file below so please check that and get back to me guys.ReFrameWork-master (1.9 MB)

It is behaving very strange, sometimes the workflow processes till the opening of file and selecting the complete action and then gets faulted and sometimes it doesn’t even do that and gets faulted. I must have made something wrong.

Please check the files guys,