Segfault during quest-reward conversation

If I choose following answers in conversation after completing a quest:

NPC: Find any antibiotics yet? You: Yup! Here it is! NPC: Oh thank god! I'll be right as rain in no time. You: Maybe you can teach me something as payment. NPC: Here's what I can teach you... You: Eh, never mind. Segmentation fault (core dumped)
it always crashes (100% cases). I dont' know how to check which version I play, but I downloaded it today from github and compiled on Ubuntu 12.04.

Here is the backtrace for that error

Program received signal SIGSEGV, Segmentation fault.
gen_responses (topic=68797032, g=0x6290020, p=0x5eb1db0) at npctalk.cpp:590
590 SUCCESS_OPINION(miss->value / (OWED_VAL * 4), -1,
(gdb) bt
#0 gen_responses (topic=68797032, g=0x6290020, p=0x5eb1db0) at npctalk.cpp:590
#1 0x00921dd1 in dialogue::opt (this=0x419f884, topic=68810644, g=0x6290020) at npctalk.cpp:1513
#2 0x00924233 in npc::talk_to_u (this=0x5eb1db0, g=0x6290020) at npctalk.cpp:118
#3 0x00555c13 in game::chat (this=0x6290020) at game.cpp:6343
#4 0x0056c6c3 in game::get_input (this=0x6290020, timeout_ms=137911408) at game.cpp:1345
#5 0x0056e1ef in game::do_turn (this=0x6290020) at game.cpp:670
#6 0x00b24148 in main (argc=1, argv=0x2f1810) at main.cpp:47