Hi,
To monitor hosts via icmp ping Zabbix 'puts' hosts with same ping parameters in group and before it starts to fping them it tries to find fping interval (-i parameter)
In case if it's not possible to find the intreval (network problems or if there is no host available from the group) Zabbix put icmpping items to unsupported state with fping error as it is. For example:

10.10.10.10 : [0], timed out (NaN avg, 100% loss)

10.10.10.10 : xmt/rcv/%loss = 1/0/100%

Especially in the case when there is simply not a single available host in the group, this behavior is confusing. After all, instead of an unsupported item, we should receive a notification about the unavailability of the host