Crash

Hello, i have this crash that happens in my server several times. Can anyone give me a hint of what might be the problem?
[code=auto:0] Core was generated by `./map-server'. Program terminated with signal 11, Segmentation fault. #0 0x08241c30 in unit_walktobl (bl=0xb2ce454c, tbl=0x0, range=3, flag=1) at unit.c:584 584 if (!unit->can_reach_bl(bl, tbl, distance_bl(bl, tbl)+1, flag&1, &ud->to_x, &ud->to_y)) { Missing separate debuginfos, use: debuginfo-install glibc-2.12-1.80.el6_3.3.i686 keyutils-libs-1.4-4.el6.i686 krb5-libs-1.9-33.el6.i686 libcom_err-1.41.12-12.el6.i686 libselinux-2.0.94-5.3.el6.i686 mysql-libs-5.1.61-4.el6.i686 nss-softokn-freebl-3.12.9-11.el6.i686 openssl-1.0.1e-16.el6_5.7.i686 pcre-7.8-4.el6.i686 zlib-1.2.3-27.el6.i686 (gdb) BT FULL #0 0x08241c30 in unit_walktobl (bl=0xb2ce454c, tbl=0x0, range=3, flag=1) at unit.c:584 ud = 0xb2ce4564 sc = 0x0 #1 0x0821ae78 in status_check_skilluse (src=0xb2ce454c, target=0xb429c404, skill_id=0, flag=0) at status.c:1660 st = 0xb2ce47b4 sc = 0xb2ce4808 tsc = <value optimized out> hide_flag = <value optimized out> #2 0x081404c6 in mob_ai_sub_hard_activesearch (bl=0xb429c404, ap=0xbff5bb6c "") at mob.c:1067 md = 0xb2ce454c target = 0xbff5bbac mode = <value optimized out> dist = <value optimized out> #3 0x08131c06 in bl_vforeach (func=0x8140470 <mob_ai_sub_hard_activesearch>, blockcount=8, max=2147483647, args=0xbff5bb60 "LEß\254\273\365\277\225\062") at map.c:505 argscopy = 0xbff5bb60 "LEß\254\273\365\277\225\062" i = 8 returnCount = <value optimized out> #4 0x0813c074 in map_foreachinrange ( ---Type <return> to continue, or q <return> to quit--- func=0x8140470 <mob_ai_sub_hard_activesearch>, center=0xb2ce454c, range=10, type=27) at map.c:766 returnCount = -1295104164 ap = 0xbff5bb60 "LEß\254\273\365\277\225\062" #5 0x0814d049 in mob_ai_sub_hard (md=0xb2ce454c, tick=298988914) at mob.c:1555 sce = <value optimized out> tbl = 0x0 abl = <value optimized out> mode = 12949 view_range = 10 can_move = 1 #6 0x08140ee0 in mob_ai_sub_hard_timer (bl=0xb2ce454c, ap=0xbff5bc88 "") at mob.c:1713 md = 0xb2ce454c tick = 298988914 #7 0x08131c06 in bl_vforeach (func=0x8140eb0 <mob_ai_sub_hard_timer>, blockcount=0, max=2147483647, args=0xbff5bc80 "r5\322\021") at map.c:505 argscopy = 0xbff5bc80 "r5\322\021" i = 1 returnCount = <value optimized out> #8 0x0813c074 in map_foreachinrange (func=0x8140eb0 <mob_ai_sub_hard_timer>, center=0xbc5b410, range=16, type=2) at map.c:766 returnCount = -1295104164 ---Type <return> to continue, or q <return> to quit--- ap = 0xbff5bc80 "r5\322\021" #9 0x08140f73 in mob_ai_sub_foreachclient (sd=0xbc5b410, ap=0xbff5bd0c "") at mob.c:1728 tick = <value optimized out> #10 0x08131ee2 in map_vforeachpc (func=0x8140f20 <mob_ai_sub_foreachclient>, args=0xbff5bd04 "r5\322\021") at map.c:2060 argscopy = 0xbff5bd04 "r5\322\021" ret = <value optimized out> iter = 0xb5d2b65c sd = 0xbc5b410 #11 0x0813bdbe in map_foreachpc (func=0x8140f20 <mob_ai_sub_foreachclient>) at map.c:2075 args = 0xbff5bd04 "r5\322\021" #12 0x08140ff6 in mob_ai_hard (tid=12, tick=298988914, id=0, data=0) at mob.c:1813 No locals. #13 0x08260196 in do_timer (tick=298988916) at timer.c:398 tid = 12 diff = -2 __FUNCTION__ = "do_timer" #14 0x08255ac4 in main (argc=1, argv=0xbff5bea4) at core.c:445 next = <value optimized out> retval = 0 [/code]


Thansk in advance for the attention. Any suggestions on how to solve it would be welcome. If need more information please let me know.

Regards.