I had a database corruption recently and was told that it may have been caused by dropping tables while the database was online with other users connected. Apparently there is some kind of race condition in the page allocation that can cause the same page to be allocated to different "things" when doing that. It ONLY concern dropping tables.

What version of firebird are you using? If it is one of the latest, would be helpful to open a ticket in the tracker in order to be solved.

I think is a serious bug corrupt a database, and more serious if it happens executing DDL statements.

Jesus Garcia