Windows 2000
DB2 7.2 w fixpack 12

I currently run an online backup every night @ 10PM which gets saved to D:\backup and we are also using the user exit program which saves old log files to D:\db2log. I then backup the 2 folders to tape at 1AM. Also I am currently backing up the SQLOGDIR which is located in D:\DB2\NODE0000\SQL00001 folder. I've heard and read several places that nothing in the DB2 folder should be getting backed up to tape but someone else told me that the SQLOGDIR folder should be getting backed up since it contains the latest log files in case a backup is needed.
The database sometimes (once every several months) crashes and I'm thinking it's because of this backup of the SQLOGDIR folder since it happens shortly after the backup to tape starts.

What is the correct method to backup??