I have the same behaviour on 2 of my Kubuntu installations.
If I comment the "up /etc/openvpn/up.sh" line in my openvpn.conf script, then it works again, and I have to execute the up.sh manually.
Wed Oct 30 20:01:07 2013 TUN/TAP device tun0 opened
Wed Oct 30 20:01:07 2013 do_ifconfig, tt->ipv6=0, tt->did_ifconfig_ipv6_setup=0
Wed Oct 30 20:01:07 2013 /sbin/ip link set dev tun0 up mtu 1500
Wed Oct 30 20:01:07 2013 /sbin/ip addr add dev tun0 local 10.242.0.10 peer 10.242.0.9
Wed Oct 30 20:01:07 2013 /etc/openvpn/up.sh tun0 1500 1560 10.242.0.10 10.242.0.9 init
Wed Oct 30 20:01:07 2013 WARNING: Failed running command (--up/--down): could not execute external program
Wed Oct 30 20:01:07 2013 Exiting due to fatal error
What did change with openvpn?
If I comment the "up /etc/openvpn/up.sh" line in my openvpn.conf script, then it works again, and I have to execute the up.sh manually.
Wed Oct 30 20:01:07 2013 TUN/TAP device tun0 opened
Wed Oct 30 20:01:07 2013 do_ifconfig, tt->ipv6=0, tt->did_ifconfig_ipv6_setup=0
Wed Oct 30 20:01:07 2013 /sbin/ip link set dev tun0 up mtu 1500
Wed Oct 30 20:01:07 2013 /sbin/ip addr add dev tun0 local 10.242.0.10 peer 10.242.0.9
Wed Oct 30 20:01:07 2013 /etc/openvpn/up.sh tun0 1500 1560 10.242.0.10 10.242.0.9 init
Wed Oct 30 20:01:07 2013 WARNING: Failed running command (--up/--down): could not execute external program
Wed Oct 30 20:01:07 2013 Exiting due to fatal error
What did change with openvpn?