[CentOS] problem clamd via rpmforge

hello list hello centos network hello all the builder of rpm's

i use clamd package via rpmforge today they are passes i use CentOS 5.5 with small system with low memory system support couple postfix/amavisd/clamd/dkimproxy/sid-milter/policyd/postgrey/dovecot2

when i restart clamd i obtain one error i quote for clarity

~]# service clamd restart Stopping Clam AntiVirus Daemon: [ OK ] Starting Clam AntiVirus Daemon: WARNING: Running on 32-bit system, and RLIMIT_DATA > 2GB, lowering to 2GB! [ OK ]

what error RLIMIT_DATA > 2GB i use 1GB swap

how to configure the machine to remove this error

thanks for all return