We had this happen to us as well. I checked a table in the database to see what was going on.
select * from Ice.RptDefault
The user in question had a few settings that didn’t quite look right. We removed those from the table, and like magic things starting working again. We think the data was from an older version of Epicor that was causing issues. We have been on 9.05 -> 10.0.700 -> 10.1.400. Anyway it is nice to learn that the set default will do the same as the database hack.
The root cause of our issue is that the report default was set to an old report number. Wonder is there is a way to identify situations like this through the client? I am guessing not.