Buy shield med vendor - playthrough 2
Is everything checked in that quest summary ? If not the only way is to do it again online with someone that didn't do it yet, or create a new character with a non online account and in Split screen do the quest with your bug quested one connected to Xbox live, it'll save anyway ;)
Man, it's been a while since I finished Zombie Island (8 times in total : 4 character x 2 playthrought)... Yeah It should be checked as soon as you killed Pumpkinhead or maybe check the dead corpse but that's it...
Did this happen in Single Player or Online ?
Yeah, unfortunatly lots of stuff like that happened when playing online, as a matter of fact I got the Tannis Bug online and You also got to be careful if you got Knoxx and play online you might end up having the 2 Armory Quest from Marcus at the same time, DON'T ACCEPT BOTH if it happens, accept one, finish it, then come back to accept the 2nd one. If you accept both, when going to the Armory the 2nd will be bugged...
That's why I prefer to do the stuff in Single Player, and when I'm done I can go online with no worry (Well except for Tannis that still come back :( )
You should try (if it's not done yet) to kill him again (He respawn) and see what happen.
What u eman when u say bugged for the armoury quest? Does that mean u can't do the glitch? CAn u finish both quest? What exactly is it
Did u try just downloading willowtree? I know ur a legit player. All ur doing is fixing a glitch not modding a weapon or something all u do is put the quest as not started that's, Ur not modding ur skill's or character in anyway.

First time I hear about something like this...
The Main Quest is divided in 3 parts :
- Get the batterie on the left of the city (where skags await for you)
- Put the batterie on the Med Vending machine
- And finally buy a Shield from that machine and return to Dr Zed
Now I don't quite understand how you could arrive in New Heaven without completing the quest (since it's a main quest) ??? Even doing extra quest online with others players to get there it should simply notify you that those quests are not available for you... Therefore you should still be in Arid Badlands...
Until now the only Quest bug I knew were the one with Tannis...
Time Spent on Borderlands : 1700 Hours +