[solved] Bug in Code, Please Help (user creation)

--A user Maker.  This will Check a password file for a user if not present it will make the user and salt their user password.

--Api's to load
os.loadAPI("sha")

--VARIABLES
--Global
  --none

--local
local fileName = "PSW" --name of password file.
--END OF VARIABLES

--FUNCTIONS
--Global
   function setScreen()-- works, This clears the screen and positions us in the top left of the terminal. This needs to be a global function.
   term.clear() -- set screen up
   term.setCursorPos(1,1)
   term.setCursorBlink(true)
   print("hello") --testing text
  end--close function

--local
  local function createFile ( )--This creates The password file if it doesnt exsit.
   setScreen()
   if not fs.exists(fileName) then --Create a password file
	  write(": File ", fileName ," Not Found")
	write(": Creating File ",fileName)
	local f = fs.open(fileName, "w")  --This creates the file in a writable state as a veriableM
	  f.write(textutils.serialize({ })) --This puts the text we want in the file
	  f.close() --This closes the file
	write (": Created File ", fileName )
   else
	write(": File ",fileName," Found")
   end
  end

  local function readFile()
   local f = fs.open(fileName,"r")
   local usrs = textutils.unserialize(f.readAll())
   f.close()-- we have now checked the file to see whos in it read and stored all the names and passwords in memorry.
   print(": ",fileName," Read")
  end

  local function userName()
   setScreen()
   readFile()
   write("UserName :: ") -- ask for username
   local u = read()--read the user password response, comit to variable u
  
   if not usrs[u] then -- we reconise its a new user and carry on and create the password
	write("password :: ") --ask for user password
	local p = read()--read the user password response, comit to variable p
  
	local salt = math.random(1,10000000000000)*math.random(1,10000000000000)
	*math.random (1,10000000000000) -- massive over kill to get a really big random number i know
  
	usrs[u] = {
		  pwd = sha.sha256( p .. salt ),
		  salt = salt,
	  }
	  local f = fs.open(passPath, "w")
	  f.write( textutils.serialize( usrs ) )
	  f.close()
   else
	write("UserName already taken")
	os.sleep(2)
	userName()
   end
  end
--END OF FUNCTIONS
--CODE

createFile(fileName) --call function and pass file name  PSW into it.
os.sleep(2)
readFile(fileName) -- Read the File PSW
os.sleep(2)
userName()
-- END OF CODE
--[[
This is my variation of CompuTech's user maker on page (How to Securely Store Passwords).
This can be found at http://www.computercraft.info/forums2/index.php?/topic/27496-how-to-securely-store-passwords/page__p__260768#entry260768
os.loadAPI("sha")
write("username :: ")
local u = read()
write("password :: ")
local p = read()
--Again, change passPath here
local passPath = "passwords"
local f = fs.open(passPath,"r")
local usrs = textutils.unserialize(f.readAll())
f.close()
if not usrs[u] then
  local salt = os.time()
  usrs[u] = {
		pwd = sha.sha256( p .. salt ),
		salt = salt,
  }
  local f = fs.open(passPath, "w")
  f.write( textutils.serialize( usrs ) )
  f.close()
end
--]]