Please help! Why would this error start appearing:-

> Error: Filename does'nt exist : bi/data/models_strat/residences/barb_large_city.CAS
> Error: Filename does'nt exist : bi/data/models_strat/residences/barb_huge_city.CAS

We are working on a mod for a vanilla RTW - not involving BI at all! Any ideas or suggestions as to what has gone awry would be gratefully received. The mod sits in its own folder directly under the Rome directory.