This failure occurs because financially-enabled resources do not have the Resource Class or Transaction Class fields set or populated with a value.
1. Run and export the results of the query to a spreadsheet:
select s.unique_name from srm_resources s
where s.id in (select p.ID from pac_mnt_resources p
where p.resource_class is null OR p.transclass is null)
2. For each resource in the results,
a. Go to Home > Resources > select resource > Properties > Financial
b. Populate the Transaction Class field
c. Populate the Resource Class field
d. Click Save
3. Rerun the upgrade.