The most common reason for this is that ZoneAlarm, a Firewall, Anti Virus Program, etc. has disabled ping (see the Q&A in Firewalls and NAT), or that you mis-typed your static IP address (visit the link "Maintain" and carefully compare the IP listed, with your public IP). Or you have a Linksys BEFSR41 (again, see Firewalls and NAT), or, you have just added yourself and there is insufficient data to create a report yet.

Also, see this faq entry: »Line Monitoring FAQ »When east or west monitoring sites are changed, do you notify people?