When doing online backups of Exchange 2003 with SP1 you may not be successful and you may get the following in your application logs:
Error -4001 During backup of a database location. The database will be unable to restore.
A new article has been posted about this here:
You cannot successfully perform an online backup information store databases on your Exchange Server 2003 SP1 computer, and event ID 217 is logged
This will update your ESE.dll to version 6.5.7232.54.
I found this article interesting because it was the first time that I had read (personally) where we recommended running "kill" against the information store instead of stopping all of the services. This is mentioned in Method 1. But then I read Method 2. There your option is to do a defragmentation of your database. If I had to choose between the two, I would go with Method 1 if I had a good backup from the day before. You do check your backup logs daily right? Yeah, I thought so... Of course if you get this version of ESE on your machine you probably will not have this issue.