As your 3rd NIC is different from the two others, you need to load the apropriate kernel module. For example, if this NIC is handled by the 3c59x kernel module, you can do the following:
cat <<'EOF' > /etc/sysconfig/network-scripts/ifcfg-eth2
TYPE=Ethernet
DEVICE=eth2
USERCTL=no
ONBOOT=no
PEERDNS=no
IPV6INIT=no
IPADDR=0.0.0.0
EOF
echo "alias eth2 3c59x" >> /etc/modprobe.conf
Then, the module should automatically load on boot, eth2 will be available, and chilli will be able to start and to create the tun0 interface.
Let me know.
Regards, Daniel