VPNC died with signal 6

2015-02-11T15:00:58.361683-02:00 UYMV00630 NetworkManager[7556]: <info> (tun0): link connected
2015-02-11T15:00:58.361902-02:00 UYMV00630 NetworkManager[7556]: <info> VPN connection ‘vpn-IMM’ (IP Config Get) complete.
2015-02-11T15:00:58.362116-02:00 UYMV00630 NetworkManager[7556]: <info> VPN plugin state changed: started (4)
2015-02-11T15:00:58.389023-02:00 UYMV00630 NetworkManager[7556]: <info> NetworkManager state is now CONNECTED_LOCAL
2015-02-11T15:00:58.389800-02:00 UYMV00630 NetworkManager[7556]: <info> NetworkManager state is now CONNECTED_GLOBAL
2015-02-11T15:00:58.395506-02:00 UYMV00630 nm-dispatcher: Dispatching action ‘vpn-up’ for tun0
2015-02-11T15:00:58.449861-02:00 UYMV00630 NetworkManager[7556]: vpnc: vpnc.c:1261: lifetime_ike_process: Assertion `a->next->type == IKE_ATTRIB_LIFE_DURATION’ failed.
2015-02-11T15:00:58.463126-02:00 UYMV00630 NetworkManager[7556]: ** (nm-vpnc-service:7968): WARNING **: vpnc died with signal 6
2015-02-11T15:00:58.623641-02:00 UYMV00630 NetworkManager[7556]: <error> [1423674058.623549] [platform/nm-linux-platform.c:1714] add_object(): Netlink error adding via dev tun0 metric 1024 mss 0 src user: No such device

after an assert error it fails with signal 6 (SIGABRT)

Your subject line suggests your focus is on the result and not the cause of your problem… which is the previous line in the log entries you posted.

If you Google the previous line you’ll return numerous results, but the following result may be a good candidate for resolution (the last 2 posts in this thread)