Any C++ guru for help, or .. is it the wrong board ?

[smogo]

Duno if it is the place to post this, but playing around with the code, i get stuck by a crash in zone :

in NPC::Process() line 521 there is a call to AI_Process(). This refers to the parent's class Mob::AI_Process(). During the call, "this" changes to a wrong value.

Below is a gbd output, where frame 1 refers to AI_Process, and frame 2 to the caller's Process(). i read that "this" turns from 0x86885e0 (correct) to 0xbffff870 (incorrect, and obviously somewhere on the stack, where it does not belong IMHO)

am i just dumb at C++ ? is it a thread related ?

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 16384 (LWP 27800)]
0x08715848 in ?? ()
Current language:  auto; currently c
(gdb) bt
#0  0x08715848 in ?? ()
#1  0x080e9833 in Mob::AI_Process() (this=0xbffff870) at MobAI.cpp:942
#2  0x080c496d in NPC::Process() (this=0x86885e0) at npc.cpp:521
#3  0x08092710 in EntityList::MobProcess() (this=0x82730a0)
    at linked_list.h:174
#4  0x080c6f9a in main (argc=5, argv=0x5f) at net.cpp:343
#5  0x4018dd06 in __libc_start_main () from /lib/libc.so.6
(gdb) frame 1
#1  0x080e9833 in Mob::AI_Process() (this=0xbffff870) at MobAI.cpp:942
942                             Mob* tmptar = entity_list.AICheckCloseArrgo(this, argo, assist);
Current language:  auto; currently c++
(gdb) print this->name
$1 = "\0\0\0\0\0\0i586\0/repository/vol313/bld/eqemu/bin/zone\0qeynos\0192.168."
(gdb) up
#2  0x080c496d in NPC::Process() (this=0x86885e0) at npc.cpp:521
521             AI_Process();
(gdb) print this->name
$2 = "Kinloc_Flamepaw's_pet00", '\0' <repeats 40 times>
(gdb) l
516                             safe_delete(hp_app);
517                     }
518             }
519
520             adverrorinfo = 3;
521             AI_Process();
522             adverrorinfo = 0;
523         return true;
524

Thanks for any help. Sry if this is not the correct forum.