Empty Graphs for some devices

[druss102]

Hello, I am running Cacti 0.8.8b with Advanced Ping 2.2. For some reason some of my devices graph with no issues and others graph with empty results. When I run ss_fping.php from the command line the results are good for all devices. But when I check the poller debug log the results are U for the device(s) that don't graph.

Ex. Good device
SERVER: /usr/share/cacti/scripts/ss_fping.php ss_fping x.x.x.x 20 ICMP , output: min:62.7720 avg:74.1263 max:156.5990 dev:24.5979 loss:0.0000

Command Line: php ss_fping.php x.x.x.x 20 ICMP
min:54.7350 avg:58.8532 max:94.7640 dev:8.7247 loss:0.0000

Ex. Bad Device (empty graph image attached to this post)
POLLER LOG: SERVER: /usr/share/cacti/scripts/ss_fping.php ss_fping x.x.x.x 20 ICMP , output: U

COMMAND LINE: php ss_fping.php x.x.x.x 20 ICMP
min:1.6790 avg:1.7230 max:1.8170 dev:0.0325 loss:0.0000a

Any advice is greatly appreciated