There are some limits in using DATA STRUCTURE in a SQLRPGLE.
As I can read before, Yes it is possible to have an array in a data Structure, however :
first of all, to use it in a fetch is impossible, the precompiler SQL do not support it,
second thing, the DS PublisherReferences is in another DS(P_IacWtlDataIPWorkList), so if the host variable used in your fetch is :P_IacWtlDataIPWorkList.PublisherReferences(n).Reference and you can not use more than one level of qualification.
You will be able to check what limits exists in that IBM reference :