[CentOS] log rotation not writing to new logs

Hello,
	I've got a centos 5.3 machine that is running services http and ftp
whih are the two services i've noticed this on. When log rotation happens
the old logs are renamed and compressed, but new logs httpd and pure-ftpd
have zero lengths. From that poing log writing is not working. I've tried
shutting down rsyslog and both httpd and pure-ftpd and restarting them, this
is not working. I am open to suggestions.
Thanks.
Dave.