> Here it is:
>
> server.domain.com (Server) Wed Sep 26 08:38:46 2007
> Database: /database.fdb
> Pointer page (sequence 0) lost in table (213)
>
> server.domain.com (Server) Wed Sep 26 08:38:52 2007
> Database: /database.fdb
> Pointer page (sequence 0) lost in table (224)
>
> server.domain.com (Server) Wed Sep 26 08:38:52 2007
> Database: /database.fdb
> Pointer page (sequence 0) lost in table (226)
>
> server.domain.com (Server) Wed Sep 26 08:38:52 2007
> Database: /database.fdb
> Pointer page (sequence 0) lost in table (228)

Very sad.

> - Are these serious errors?

Yes. Four tables is not acessible (but it not means they can't be recovered)

> - Can i recover them without doing a backup/restore?

I doubt you can

> - Do someone have any clue of what can cause there kind of errors?

I never see such errors

> - Can i keep working for some hours with them there?

You may query RDB$PAGES to look for lost pointer pages

SELECT * FROM RDB$PAGES
WHERE RDB$PAGE_TYPE = 4
AND RDB$PAGE_SEQUENCE = 0
AND RDB$RELATION_ID = ?

It is very small chance that you found something, but you may try.

Also you may contact ib_aid team for help.

Regards,
Vlad