I suspect this is while running the dbscripts/xml/upgrade/1.2.0.0_update.xml script, right? It tries to introduce a default setting where versions of OMP previous to 1.2.0 didn’t have anything. Is it possible that your database was previously partially upgraded to OMP 1.2.0 or later and wasn’t restored from backup afterward? An OMP 1.1.1.1 database shouldn’t have any reference to coverThumbnailsMaxWidth in its code/database.
Regards,
Alec Smecher
Public Knowledge Project Team