diff -uwr nethack-linux/include/extern.h nethack-thrown-potion-iron-bars-crash-C343-100/include/extern.h
--- nethack-linux/include/extern.h	2008-05-26 19:47:02.000000000 +0200
+++ nethack-thrown-potion-iron-bars-crash-C343-100/include/extern.h	2008-12-28 08:55:50.000000000 +0100
@@ -2367,7 +2367,7 @@
 E void FDECL(hit, (const char *,struct monst *,const char *));
 E void FDECL(miss, (const char *,struct monst *));
 E struct monst *FDECL(bhit, (int,int,int,int,int (*)(MONST_P,OBJ_P),
-			     int (*)(OBJ_P,OBJ_P),struct obj *));
+			     int (*)(OBJ_P,OBJ_P),struct obj *, boolean *));
 E struct monst *FDECL(boomhit, (int,int));
 E int FDECL(burn_floor_paper, (int,int,BOOLEAN_P,BOOLEAN_P));
 E void FDECL(buzz, (int,int,XCHAR_P,XCHAR_P,int,int));
diff -uwr nethack-linux/src/apply.c nethack-thrown-potion-iron-bars-crash-C343-100/src/apply.c
--- nethack-linux/src/apply.c	2008-05-26 19:47:02.000000000 +0200
+++ nethack-thrown-potion-iron-bars-crash-C343-100/src/apply.c	2008-12-28 11:03:52.000000000 +0100
@@ -80,7 +80,7 @@
 	} else if ((mtmp = bhit(u.dx, u.dy, COLNO, FLASHED_LIGHT,
 				(int FDECL((*),(MONST_P,OBJ_P)))0,
 				(int FDECL((*),(OBJ_P,OBJ_P)))0,
-				obj)) != 0) {
+				obj, NULL)) != 0) {
 		obj->ox = u.ux,  obj->oy = u.uy;
 		(void) flash_hits_mon(mtmp, obj);
 	}
@@ -670,7 +670,7 @@
 	mtmp = bhit(u.dx, u.dy, COLNO, INVIS_BEAM,
 		    (int FDECL((*),(MONST_P,OBJ_P)))0,
 		    (int FDECL((*),(OBJ_P,OBJ_P)))0,
-		    obj);
+		    obj, NULL);
 	if (!mtmp || !haseyes(mtmp->data))
 		return 1;
 
diff -uwr nethack-linux/src/dokick.c nethack-thrown-potion-iron-bars-crash-C343-100/src/dokick.c
--- nethack-linux/src/dokick.c	2008-05-26 19:47:02.000000000 +0200
+++ nethack-thrown-potion-iron-bars-crash-C343-100/src/dokick.c	2008-12-28 11:08:50.000000000 +0100
@@ -553,7 +553,7 @@
 	mon = bhit(u.dx, u.dy, range, KICKED_WEAPON,
 		   (int FDECL((*),(MONST_P,OBJ_P)))0,
 		   (int FDECL((*),(OBJ_P,OBJ_P)))0,
-		   kickobj);
+		   kickobj, NULL);
 
 	if(mon) {
 	    if (mon->isshk &&
diff -uwr nethack-linux/src/dothrow.c nethack-thrown-potion-iron-bars-crash-C343-100/src/dothrow.c
--- nethack-linux/src/dothrow.c	2008-05-26 19:47:02.000000000 +0200
+++ nethack-thrown-potion-iron-bars-crash-C343-100/src/dothrow.c	2008-12-28 18:06:30.000000000 +0100
@@ -980,14 +980,17 @@
 
 		if (Underwater) range = 1;
 
+		boolean obj_destroyed = FALSE;
 		mon = bhit(u.dx, u.dy, range, THROWN_WEAPON,
 			   (int FDECL((*),(MONST_P,OBJ_P)))0,
 			   (int FDECL((*),(OBJ_P,OBJ_P)))0,
-			   obj);
+			   obj, &obj_destroyed);
 
 		/* have to do this after bhit() so u.ux & u.uy are correct */
 		if(Is_airlevel(&u.uz) || Levitation)
 		    hurtle(-u.dx, -u.dy, urange, TRUE);
+
+		if (obj_destroyed) return; /* fixes C343-100 */
 	}
 
 	if (mon) {
@@ -1748,7 +1751,7 @@
 			mon = bhit(u.dx, u.dy, range, THROWN_WEAPON,
 				   (int FDECL((*),(MONST_P,OBJ_P)))0,
 				   (int FDECL((*),(OBJ_P,OBJ_P)))0,
-				   obj);
+				   obj, NULL);
 			if(mon) {
 			    if (ghitm(mon, obj))	/* was it caught? */
 				return 1;
diff -uwr nethack-linux/src/zap.c nethack-thrown-potion-iron-bars-crash-C343-100/src/zap.c
--- nethack-linux/src/zap.c	2008-05-26 19:47:02.000000000 +0200
+++ nethack-thrown-potion-iron-bars-crash-C343-100/src/zap.c	2008-12-28 18:06:07.000000000 +0100
@@ -2467,7 +2467,7 @@
 	    } else if (u.dz) {
 		disclose = zap_updown(obj);
 	    } else {
-		(void) bhit(u.dx,u.dy, rn1(8,6),ZAPPED_WAND, bhitm,bhito, obj);
+		(void) bhit(u.dx,u.dy, rn1(8,6),ZAPPED_WAND, bhitm,bhito, obj, NULL);
 	    }
 	    /* give a clue if obj_zapped */
 	    if (obj_zapped)
@@ -2615,16 +2615,18 @@
  *  one is revealed for a weapon, but if not a weapon is left up to fhitm().
  */
 struct monst *
-bhit(ddx,ddy,range,weapon,fhitm,fhito,obj)
+bhit(ddx,ddy,range,weapon,fhitm,fhito,obj,obj_destroyed)
 register int ddx,ddy,range;		/* direction and range */
 int weapon;				/* see values in hack.h */
 int FDECL((*fhitm), (MONST_P, OBJ_P)),	/* fns called when mon/obj hit */
     FDECL((*fhito), (OBJ_P, OBJ_P));
 struct obj *obj;			/* object tossed/used */
+boolean *obj_destroyed;			/* has object been deallocated? Pointer to boolean, may be NULL */
 {
 	struct monst *mtmp;
 	uchar typ;
 	boolean shopdoor = FALSE, point_blank = TRUE;
+	if (obj_destroyed) { *obj_destroyed = FALSE; }
 
 	if (weapon == KICKED_WEAPON) {
 	    /* object starts one square in front of player */
@@ -2668,6 +2670,7 @@
 		    hits_bars(&obj, x - ddx, y - ddy,
 			      point_blank ? 0 : !rn2(5), 1)) {
 		/* caveat: obj might now be null... */
+		if (obj == NULL && obj_destroyed) { *obj_destroyed = TRUE; }
 		bhitpos.x -= ddx;
 		bhitpos.y -= ddy;
 		break;