Alexandre wrote
<<

> What are page types 7 and 5 ?

Take a look at thie thread:
http://firebird.1100200.n4.nabble.com/page-nnn-is-of-wrong-type-expected-7-found-5-td1127715.html

Perhaps it helps you. Nickolay said it could "fix" the corrupted
database only rebuilding the indices, but in some cases there is data
corruption :(

Hope you have just index corruption.

>>

Yes, that's probably it.
I emptied the table, then backup+restore. After that, the database
behaved well - I could now recreate the contents of the table. Thank you.

--
Aage J.