zabbix ping No route to host

[supertek]

Hello,
I have an issue with the 1.8.3 release installed on Ubuntu server 11.04.
My problem is that when I want to Ping my hosts from a map (right click on the host --> Ping) I get this error message : No route to host.
But i can ping this host from the machine (Ubuntu server),...

[kokomo]

On the console I go to Monitoring -> Maps -> click on an active computer and select Ping.

Then a new window opens and says Error Description: Permission denied
Ping: /bin/ping -c 3 x.x.x.x

FPING is working fine on this server.
What could cause this problem?...