Okay, now that I've spent many hours trying to track down any suggestion to resolve this problem, and I've tried everything I can think of (such as #DEFINE and so on), I have to ask the UT community:

When I have an array reference in a report form
( for example, my_array[1,2] )
then, after the build I get an "error" listed in the error log:

---> Report my_repo.frx has the following errors:
---> Unknown MY_ARRAY - Undefined

Is there a way to avoid this "undefined" message during a build?