I'm running Debian 4.0 r1 etch with syslog-ng installed instead of sysklogd...

I've noticed that the daily log rotation of my system logs is fumbled up. Since installing syslog-ng, I noticed that its daemon ceases to run after the daily logrotate cronjob runs. When I do a listing of /var/log, I'll typically see the gzipped logs and a syslog file, but the unzipped file has no content (0 filesize).

Not knowing how to first troubleshoot the problem, I started with lengthening the rotation to a weekly basis via /etc/logrotate.d/syslog-ng. That, as I found, only delayed the inevitable. At this point, I'm convinced it's a problem with the rotation script, but I don't know enough about administering linux boxes. Simply messing with configuration files didn't help, and I obviously have no system logs that would help me follow leads!

Here's what the logrotate.d file looks like:
/var/log/syslog {
rotate 7
daily
compress
postrotate
/etc/init.d/syslog-ng reload > /dev/null 2>&1
endscript
}

Based on googling, this seems pretty normal. Any ideas what would cause the process to not come back up?