parallel.waitForAll() not running

--[[ Title: Advanced Wireless Mining Turtle (TurtleSide)

Description: Mines a shaft and places ladders.
Excavates a 3 wide and 16 high passage for mining.
It knows the pattern to expose all blocks in a chunk.
and is able to make a walk way for accessing each tunnel.
It will hopefully do this while taking commands from
a computer with a wireless modem.

Author: margeobur (some code is based on default programs
for things like digging the mineshaft) ]]

local tArgs = { ... }
if #tArgs ~= 1 then
print("Usage: TurtleMining <Monitor Computer's ID> ")
return
end

local monitorID = tonumber( tArgs[1] )
if monitorID < 0 then
print("Error: Cannot have negative ID")
end


-- ***********************Functions**********************************

--*******************Monitor Communication*****************

local function receive()
while true do
local sender, message, distance = rednet.receive()
if sender ~= monitorID then
rednet.send(sender, "You are not my monitor!")

end

if message == "CheckStatus" then
local Status = getStatus()
local sStatus = textutils.serialze(Status)
rednet.send(monitorID, sStatus)

elseif message == "StopMining" then
command = 2
break

else rednet.send(monitorID, "Unknown command")

end
return
end

local function getStatus()
local x, y, z = gps.locate(4)
if not x then
x, y, z = "Could not locate", "Could not locate", "Could not locate"
end
local fuel = turtle.getFuelLevel()
local inv_room = 0
for i = 4, 9 do
inv_room = inv_room + turtle.getItemSpace(i)
end
local tStatus = readonlytable { fuel, blocks_mined, stage, inv_room, x, y, z }

return tStatus
end


--*********Digging Mineshaft/Making Mine Room*************


local function collect()
blocks_mined = blocks_mined + 1

for n=1,9 do
if turtle.getItemCount(n) == 0 then
return true
end
end

print( "No empty slots left." )
return false
end


local function tryForwards()
while not turtle.forward() do
if turtle.dig() then
if not collect() then
return false
end
   else
-- give sand a chance to fall
  sleep(0.8)
	if turtle.dig() then
	if not collect() then
return false
end
	else
	return false
   end
   end
end
xPos = xPos + xDir
zPos = zPos + zDir
return true
end


local function tryDown()
if not turtle.down() then
if turtle.digDown() then
if not collect() then
return false
end
   end
if not turtle.down() then
return false
end
end
depth = depth - 1
return true
end


local function turnLeft()
turtle.turnLeft()
xDir, zDir = -zDir, xDir
end

local function turnRight()
turtle.turnRight()
xDir, zDir = zDir, -xDir
end

local function placeLadders()
print("place de laddars")
end

local function DigShaft()
stop = false
depth = 0
blocks_mined = 0

xPos,zPos = 0,0
xDir,zDir = 0,1
alternate = 0

stage = "Digging Shaft"

print("Digging de shaft...")

while not stop do
for n = 1,3 do
for m = 1,2 do
if not tryForwards() then
stop = true
break
end
end
if stop then
break
end
if n < 3 then
if math.fmod(n + alternate,2) == 0 then
turnLeft()
if not tryForwards() then
stop = true
break
end
turnLeft()
else
turnRight()
if not tryForwards() then
stop = true
break
end
turnRight()
end
end
end

if stop then
break
end


if alternate == 0 then
turnLeft()
else
turnRight()
end

alternate = 1 - alternate

if not tryDown() then
stop = true
break
end

if command == 2 then
print("Master has told us to stop. Stopping...")
stop = true
break
end

end
end
return
end


--*********************Driver Program:*******************************


print("Welcome to margeobur's Advanced Turtle ")
print("mining program (turtleside interface)  ")
print()

rednet.open("right")
command = 0

parallel.waitForAll (DigShaft, receive)