sory im new in here

i write wed plugin.
//////////////////
void komut_isle(int id,OBJECTINFO *oi)
{
//material ayarlama, şimdilik sadece bu var
if (komutlar[id].komut_id==1)
{
CObjEditInterface *oei=gp_WedInterface->object_GetEditInterface();

oei->obje_SelectObjID(oi->Id,true);
MODELINFO mi;
oei->obje_GetInfo (&mi);
strncpy(mi.String1,komutlar[id].komut_data,30);
strcpy(mi.String2,"ddd"); //this line crash
}
}
////////////////////////
i can change String1 but cant change String2
why?

please help.

(sory for bad english)