Please ask DBA to perform below steps and let us know.
1. Run adcgnjar utility.
2. OA Core and middleware bounce.
How I can run the two steps !!
My suggestion take help of DBA for this if you new to this.
Check this link for r12.2 migration steps: chamarthi chiranjeevi oracle applications technical blog: Deployment of OAF Pages in EBS 12.2.4, 12.2.5
Separate thread should be created for new issue