You need to install the routines that automatically reload the Certificate Revocation Lists periodically from the CAs. The routines are in the edg-utils-system RPM.
You should find the correct version of this package according to your system.
For example the file:
http://datagrid.in2p3.fr/distribution/autobuild/ i386-rh7.3/wp6/RPMS/edg-utils-system-1.5.0-1.noarch.rpmis the appropriate choice for a Redhat 7.3 x86 Linux system.
The crl update can be run with command
${EDG_LOCATION}/sbin/edg-fetch-crl -o /etc/grid-security/certificates/
The cron job can be set manually using command
crontab -e
and the cron entry for crl update should for example look like:
53 1,7,13,19 * * * /opt/edg/etc/cron/edg-fetch-crl-cron
Make sure your cron is running.