How do I troubleshoot a FRM-30085 error in a form with no compilation errors

I have a form that both the Form Builder and the separate Forms Compiler refuse to compile, almost all the time.  This is one of 75 Forms modules in the application suite, and this is the only one that exhibits this problem. This module, as with all the rest, originated as an older form from several versions back.  Only since the most recent migration from 10.x to 11.1.2.1 Forms 9 months ago it has generated a "FRM-30085 Unable to adjust form for output".  It also generates a "PDE-PER001 Internal Error (depep 2)." error much, but not all of the time.  In no case has there been an error in any of the (PL/SQL) code or other components