I backuped my blog today (from the admin panel)... and curiously the backup file was smaller than the previous one. So I opened it and saw that some entries where not backuped.
It’s entries whose date is after today, but are ready for automatic publication in the next weeks. One of them is totally absent, and for another only the title is here, but not the text.

Are you running EE 1.1?  Just tried this on the dev sites with various settings (file, zipped, screen, etc.) and they all looked fine.

Yes, I am using the last version of EE with standard parameters.

The only thing I can think of is that there is code in there that cleans up the output from the database and it might be removing some of your data by accident.  Not sure why it would do an entire title for an entry though.

Perhaps you should send me an email and I can look at it myself.

An email with the backup file?

No with a login to the Control Panel so I can do the backup and compare against the entry data.