I followed the tutorial and when i tried to load my map i got the following error:

script runtime error
(see console for details)
unknown item 'zombie_perk_bottle_deadshot'

Anyone know why i am getting this?
If there is anything else you need me to post...

Thanks for the replies the bug fixed its self somehow  ???  no idea why but im getting on with my map again now

I have recently started making my own zombie map all has been going very well, i have many rooms and doors. I have fixed all the lighting and done all the zoning however today i have tried to add another window and barrier (i currently have 3) so i copied one of my existing barriers and put it into ...