Redacted. See follow on post.

----** On SceneLoad Startup Lua **----

--* global vars *--
gVETT={}; -- root namespace\table to store you stuff.
gVETT.spointtables={
[1]={latmin=20.0,latmax=62.0,lonmin=-79.0,lonmax=-50.0},
[2]={latmin=20.0,latmax=62.0,lonmin=-96.0,lonmax=-83.0}
}; 

--type,dbid and minspawnelev required. maxspawnelev,mindepth and maxdepth optional.
--maxspawnelev = if included the max depth the unit can be spawned at, only really useful for wrecks in this sample. 
--maxdepth = 0 means use elevation as max depth. fyi units will not stay below their crush\max depth.
--mindepth = 0 means use -1.0 as min depth.
--if either is missing unit is considered a ship and gets no random depth set.
--bottomout existing and set to true means spawn it at the minium elevation. (ie sea bottom if the unit allows it)
--#4 for example can produce 'boyant wrecks', #5 will not but will be obvious false contacts if the bottom is > 500 meters.
gVETT.FakeContactUnitsData = {
[1]={type="Sub",dbid=355,maxdepth=-300,mindepth=-20.0,minspawnelev=-250.0},
[2]={type="Sub",dbid=92,maxdepth=-300,mindepth=-10.0,minspawnelev=-250.0},
[3]={type="Sub",dbid=354,maxdepth=-300,mindepth=-10.0,minspawnelev=-250.0},
[4]={type="Sub",dbid=654,maxdepth=-1000,mindepth=-100.0,minspawnelev=-250.0},
[5]={type="Sub",dbid=654,maxdepth=0,mindepth=-250.0,minspawnelev=-250.0,maxspawnelev=-1000.0,bottomout=true},
[6]={type="Ship",dbid=3270,minspawnelev=-120.0},
[7]={type="Ship",dbid=3127,minspawnelev=-250.0},
[8]={type="Ship",dbid=3122,minspawnelev=-250.0}
}

gVETT.FakeNamePrefix="Fake Contact #"; -- name prefix to give each unit.
gVETT.FakeNameCounter=0;  -- gets added to each unit, incremented on generation. may want to to save to storage key on change which is not demo'd 
gVETT.dbglevel = 1; -- 0 for no logging but errors, 1 for printing to log at various steps.
--* end global vars *--

--* Global functions *--

-- Function to set a unit to a random depth given what is allowed for the unit vs actual depth.
function gVETT.SetRandomAllowedDepth(u,idx,elev)
  local fn="gVETT.GetRandomAllowedDepth(): ";
  if u ==nil or idx==nil or elev==nil then print(fn .. "Invaild params, aborting."); return false; end
  if (gVETT.FakeContactUnitsData[idx] == nil) or gVETT.FakeContactUnitsData[idx].maxdepth ==nil or gVETT.FakeContactUnitsData[idx].mindepth ==nil then return false; end
  local maxdepth = gVETT.FakeContactUnitsData[idx].maxdepth;
  local mindepth = gVETT.FakeContactUnitsData[idx].mindepth;
  if (maxdepth == nil) or maxdepth >=0 or maxdepth <= elev then maxdepth = elev; end;
  if (mindepth == nil) or mindepth >=0 or mindepth <= elev then mindepth = -1.0; end;
  if (gVETT.FakeContactUnitsData[idx].bottomout~=nil) and gVETT.FakeContactUnitsData[idx].bottomout==true then mindepth,maxdepth=elev,elev;end
  if (elev <= -1.0) and gVETT.FakeContactUnitsData[idx].type == "Sub" then 
    local r = math.random(maxdepth,mindepth)
    local r2 = r *-1;
    local retval = pcall(ScenEdit_SetUnit,{guid=u.guid, moveto=false,desiredAltitude=r,manualAltitude=r,depth=r2}); --forces specific depth for desired and current. 
    if retval ==false then 
      print(string.format("%sCould not set depth for unit. unitname:%s idx:%s elev:%s,randomdepth:%s",fn,tostring(u.name),tostring(idx),tostring(elev),tostring(r))); 
      return false;
    else
      if gVETT.dbglevel > 0 then print(string.format("%sSet random depth for unit. unitname:%s idx:%s elev:%s,randomdepth:%s",fn,tostring(u.name),tostring(idx),tostring(elev),tostring(r))); end
     return true;
    end
  end
  return false;
end

-- Function to Get random location between set of lan and lon's that is at least <= depth.
-- Returns 2 numeric values representing the chosen latitude and longitude of a qualifitying lat and lon
function gVETT.GetARandomValidLocationAtDepth(latstart,latend,lonstart,lonend,mindepth,maxdepth)
  local fn = "gVETT.GetARandomValidLocationAtDepth(): "
  if latstart==nil or latend==nil or lonstart==nil or lonend ==nil or mindepth ==nil then print(fn .. "One or more invalid params passed,aborting."); return nil,nil,nil;end
  if maxdepth == nil then maxdepth=-36000; end
  local lat_var,lonvar,newlat,newlon;
  for i = 1,10000 do
    lat_var = math.random(1,(10^5))  -- more then 10^5 is pointless for elevation grabs in cmo.
    lon_var = math.random(1,(10^5))
    newlat=math.random(latstart, latend)+(lat_var/10^5)
    newlon=math.random(lonstart, lonend)+(lon_var/10^5)
    ndepth=World_GetElevation({latitude=newlat, longitude=newlon})
    if ndepth <= mindepth and ndepth >= maxdepth then 
      if gVETT.dbglevel > 0 then print("found on try #".. tostring(i)); end
      return newlat,newlon,ndepth;
    end
  end
  print(fn .. "Could not obtain a valid location after 10000 attempts.");
  return nil,nil,nil;  
end 

-- Function to spawn a random false contact.
-- Returns a unitwrapper of the unit spawned if successful, nil otherwise.
function gVETT.SpawnRandomFalseContact(theSidename,spoint)
  local fn = "gVETT.SpawnFalseContact(): "
  local n=math.random(1,#gVETT.FakeContactUnitsData);
  if gVETT.dbglevel > 0 then print("Chose spawn location table #" .. tostring(n)); end
  if (spoint == nil) or spoint < 1 then spoint=math.random(1,#gVETT.spointtables) end;
  local stype,ndbid = gVETT.FakeContactUnitsData[n].type, gVETT.FakeContactUnitsData[n].dbid;
  local newlat,newlon,newelv = gVETT.GetARandomValidLocationAtDepth(gVETT.spointtables[spoint].latmin,gVETT.spointtables[spoint].latmax,
gVETT.spointtables[spoint].lonmin,gVETT.spointtables[spoint].lonmax, gVETT.FakeContactUnitsData[n].minspawnelev,gVETT.FakeContactUnitsData[n].maxspawnelev);
  if gVETT.dbglevel > 0 then print("Chosen type:" .. tostring(stype) .. "Chosen dbid:" ..tostring(ndbid)); end
  if stype == nil or ndbid==nil then print(fn .. "Could not obtain type or dbid, aborting."); return; end
  if newlat==nil or newlon==nil or newelv==nil then print(fn .. "newlat or newlon or newelv were invalid. aborting."); return; end
  gVETT.FakeNameCounter= gVETT.FakeNameCounter +1;
  local thename = gVETT.FakeNamePrefix .. tostring(gVETT.FakeNameCounter);
  local retval,u = pcall(ScenEdit_AddUnit,{side=theSidename, name=thename, type=stype, dbid=ndbid, latitude=newlat, longitude=newlon});
  if (retval==false) or u==nil then
    print(fn .. "AddUnit Failed to create the unit!");
  elseif(retval==true) and u~=nil then 
    if gVETT.dbglevel > 0 then print(fn .. "AddUnit Succeeded in generating unit " ..tostring(u.name) .. " with guid: " .. tostring(u.guid)); end
    gVETT.SetRandomAllowedDepth(u,n,newelv);
    return u;
  end
end

--* End global functions *-


--* SAMPLE Usage either at the end of the startup routine or elsewhere in your events\scripts. * --
local u;
gVETT.GenerateFalseContacts={} -- Just an example global if say you wanted to store these units for say later movement, storage to keys etc. 
for i= 1,10 do --spawn 10 of them as a test.
  -- gVETT.SpawnRandomFalseContact('contacts') --if you don't need the return value 
  u = gVETT.SpawnRandomFalseContact('contacts'); --if you do need it for something such as changing something later.
  --u = gVETT.SpawnRandomFalseContact('contacts',2); --optionally specify which location bounds to use.
  if (u~=nil) then
    --save for later use 
    table.insert(gVETT.GenerateFalseContacts,{name=u.name,guid=u.guid});
  end
  u=nil;
end

quote:

ORIGINAL: michaelm75au

It is probably a variable scope thing.

Add these locals to the top of the code, and remove the 'local' from where you are setting the values
local ndbid
local ttype