Suggest you move your question under Solutions/Risk and Fraud/SAS Risk Management
From what I understand and based on the error message, I believe you are on the right track. My first question would be: Has it ever worked before? What changed since?
If you can amend the code and add %include ...../source2; and also try to run in debug mode and with options mprint
I the Viya version is now called ACL and that IRM has been replaced so you must be running a solution version under SAS 9.4. CAS is Viya only.
It's too long ago that I actually did hands-on IFRS9 work and it's certainly a specialty skill. Eventually ask SAS Tech Support directly because I don't expect too many people here in the forums to know the solution in the depth needed to support you.