Stack of runtime error fixes.

Didn't feel like digging into the DNA code to find the cause of one of the errors I got sent, if anyone feels like taking a crack at it:

runtime error: list index out of bounds
proc name: updateappearance (/proc/updateappearance)
  source file: dna.dm,257
  usr: Walter Bishop (/mob/living/carbon/human)
  src: null
  call stack:
updateappearance(Walter Bishop (/mob/living/carbon/human), "0FF0000660FF000066DC0000000000...")
Walter Bishop (/mob/living/carbon/human): Transform()

What I know: He was a changeling transforming between DNAs, apparently he somehow got a set of hair DNA that was literally off the charts for determining what hairstyle it was

git-svn-id: http://tgstation13.googlecode.com/svn/trunk@781 316c924e-a436-60f5-8080-3fe189b3f50e

code/FEA/FEA_fire.dm

@@ -138,6 +138,7 @@ obj
 			sd_SetLuminosity(3)
 
 		Del()
+			if (!istype(loc, /turf/space))
 				loc:active_hotspot = null
 				src.sd_SetLuminosity(0)
 				loc = null

code/FEA/FEA_system.dm

@@ -145,7 +145,7 @@ datum
 						active_singletons += T
 
 			setup()
-
+				set background = 1
 				world << "\red \b Processing Geometry..."
 				sleep(1)
 

code/WorkInProgress/Chemistry-Holder.dm

@@ -181,9 +181,9 @@ datum
 							if(isobj(A)) spawn(0) R.reaction_obj(A, R.volume+volume_modifier)
 					if(INGEST)
 						for(var/datum/reagent/R in reagent_list)
-							if(ismob(A)) spawn(0) R.reaction_mob(A, INGEST, R.volume+volume_modifier)
+							if(ismob(A) && R) spawn(0) R.reaction_mob(A, INGEST, R.volume+volume_modifier)
-							if(isturf(A)) spawn(0) R.reaction_turf(A, R.volume+volume_modifier)
+							if(isturf(A) && R) spawn(0) R.reaction_turf(A, R.volume+volume_modifier)
-							if(isobj(A)) spawn(0) R.reaction_obj(A, R.volume+volume_modifier)
+							if(isobj(A) && R) spawn(0) R.reaction_obj(A, R.volume+volume_modifier)
 				return
 
 			add_reagent(var/reagent, var/amount, var/data=null)

code/WorkInProgress/Chemistry-Reagents.dm

@@ -105,9 +105,9 @@ datum
 					if(D)
 						blood_prop.virus = new D.type
 						blood_prop.virus.holder = blood_prop
-					if(istype(T, /turf/simulated/floor))
+					if(istype(T, /turf/simulated/floor) && D)
 						blood_prop.virus.spread_type = CONTACT_FEET
-					else
+					else if (D)
 						blood_prop.virus.spread_type = CONTACT_HANDS
 
 				else if(istype(self.data["donor"], /mob/living/carbon/monkey))
@@ -184,7 +184,7 @@ datum
 							T:wet_overlay = null
 
 				var/hotspot = (locate(/obj/hotspot) in T)
-				if(hotspot)
+				if(hotspot && !istype(T, /turf/space))
 					var/datum/gas_mixture/lowertemp = T.remove_air( T:air:total_moles() )
 					lowertemp.temperature = max( min(lowertemp.temperature-2000,lowertemp.temperature / 2) ,0)
 					lowertemp.react()
@@ -195,7 +195,7 @@ datum
 				src = null
 				var/turf/T = get_turf(O)
 				var/hotspot = (locate(/obj/hotspot) in T)
-				if(hotspot)
+				if(hotspot && !istype(T, /turf/space))
 					var/datum/gas_mixture/lowertemp = T.remove_air( T:air:total_moles() )
 					lowertemp.temperature = max( min(lowertemp.temperature-2000,lowertemp.temperature / 2) ,0)
 					lowertemp.react()

code/defines/obj/toy.dm

@@ -162,6 +162,7 @@ obj/item/toy/blink
 			playsound(user.loc, 'syringeproj.ogg', 50, 1)
 
 			for(var/i=0, i<6, i++)
+				if (D)
 					if(D.loc == trg) break
 					step_towards(D,trg)
 

code/game/machinery/shieldgen.dm

@@ -179,7 +179,9 @@
 		return 0
 	var/turf/T = src.loc
 	var/obj/cable/C = T.get_cable_node()
-	var/net = C.netnum		// find the powernet of the connected cable
+	var/net
+	if (C)
+		net = C.netnum		// find the powernet of the connected cable
 
 	if(!net)
 		power = 0

code/game/magic/cultist/rune3.dm

@@ -14,6 +14,7 @@
 			V.show_message("\red [M] writhes in pain as the markings below him glow a bloody red.", 3, "\red You hear an anguished scream.", 2)
 		M << "<font color=\"purple\"><b><i>Your blood pulses. Your head throbs. The world goes red. All at once you are aware of a horrible, horrible truth. The veil of reality has been ripped away and in the festering wound left behind something sinister takes root.</b></i></font>"
 		M << "<font color=\"purple\"><b><i>Assist your new compatriots in their dark dealings. Their goal is yours, and yours is theirs. You serve the Dark One above all else. Bring It back.</b></i></font>"
+		if (ticker.mode.name == "cult")
 			ticker.mode:grant_runeword(M)
 		cultists.Add(M)
 		return

code/game/objects/effect_system.dm

@@ -662,6 +662,7 @@ steam.start() -- spawns the effect
 			F.amount = amount
 			if(!metal)
 				F.create_reagents(10)
+				if (reagents)
 					for(var/datum/reagent/R in reagents.reagent_list)
 						F.reagents.add_reagent(R.id,1)
 		sleep(15)

code/modules/mob/dead/observer/observer.dm

@@ -44,7 +44,7 @@
 	..()
 	statpanel("Status")
 	if (src.client.statpanel == "Status")
-		if(ticker.mode != null)
+		if(ticker.mode)
 			//world << "DEBUG: ticker not null"
 			if(ticker.mode.name == "AI malfunction")
 				//world << "DEBUG: malf mode ticker test"