ORA - 06508 error in forms 12c

We are migrating from Forms 6i to 12c.  I have successfully installed 12c and even the test form runs properly.  However, when I run one of my old forms of Forms 6i, it gives me the error ‘FRM-40735 – ON-ERROR TRIGGER RAISED UNHANDLED EXCEPTION – ORA 06508’.  The form even compiles properly.  All my libraries are inside

\ORACLE\Middleware\Oracle_Home\forms\forms which I have included in  FORMS_PATH registry.  What could be the problem? Any help would be appreciated.  The error becomes even before the WHEN-NEW-FORMS-INSTANCE is executed.  I am successfully connecting to the database where all program units are properly compiled.