thanks for the response. I wasn't getting any error because I did what the instructions says.
I set "saver="matrix" and "blanktime="300" in /etc/rc.conf. Reboot my box and waited for 5 minutes and the screen saver didn't work. Did any of you two tried that matrix screen saver on your FreeBSD box? I provided a link where you can get it and it has the instructions also when you scroll down the bottom page.