Constructs an instance of this class. This constructor should be used
when an operation involving one file fails and there isn't any additional
information to explain the reason.
Parameters:
file - a string identifying the file or null if not known.
Constructs an instance of this class. This constructor should be used
when an operation involving two files fails, or there is additional
information to explain the reason.
Parameters:
file - a string identifying the file or null if not known.
other - a string identifying the other file or null if there
isn't another file or if not known
reason - a reason message with additional information or null