I am being asked to do this from the Oracle Engineer, but what he doesn’t know or remember is that we have 98 stand-alone instances of Primavera P6 installed, that connect to an Oracle 11G Database.
How is it possible to do this to 98 desktop via some sort of mass delpoyment or GPO or script of some sort?
Yes, this is because the password is expiring because of a configuration of the database. You will be able to log into P6 administrator if you change the privuser password, but you need to update the alias in every machine where p6 windows client is installed and update password of the privuser with the database configuration application (administer private database logins option).
You can refer to the following KM note for possible solution to this different issue:
Error: "Bad public user name or password. Database Server Error: ORA-28001: the password has expired" Connecting To Project Management Database (Doc ID 1377730.
If you are using pubuser for P6 client connection then you may not have to do on all machines. You can try this
1. Reset pubuser password at database level to the same as earlier one
2. Change the privuser password using the utility mentioned by Oracle support. It is saved in database table so you do not have to change that on individual machine
Even if you are using privuser for p6 client then also you need to reset it at database level and only once using the utility.