Steps to reproduce:

1. From the problems list or latest data or similar, choose a host on IPv6
2. Click the host and choose ping

Result:
Ping fails, script error
Expected:
Ping should work on both protocols.
Proposed fix:
Replace the ping script with something checking for protocol on machines with older iputils. I resorted to using an external script, since writing the script in the script editor in zabbix didn't allow for expanding variables. This is perhaps another bug I should report. The script I wrote, was simply this:

#!/bin/bash

if $( echo $1 | grep -q ':' )
then
    OPTS=-6
fi

1. echo $1 | grep -q ':' && OPTS='-6'
   ping $OPTS -c 3 $1
   case $? in
       [01])
           true
           ;;
       *)
           false
           ;;
   esac