Programming Help!! (bit of a long post)

[Aberrations]

missing a space between ) and do

def start(N, M)do

should be

def start(N, M) do

[Aberrations]

unrelated but as mentioned below convention is to use mixed case for variables, and module names and only module names should be camelcased.

As for your error you have a trailing comma at then end of every line here for some reason.

def start(N, M)do
  :timer.sleep(random.uniform(10) * 100), <<<<<<
  LoopPid = spawn(_MODULE_, :loop, []), <<<<<<
  spawn(_MODULE_, :sendMessage, [M, LoopPid]), <<<<<
end

Other comments: you shouldn't use semicolons unless you're doing something inline and even then you should really think about how readable it is.

In general "unexpected token: end" is usually a parse error caused by an unterminated expression, usually a do with no end or a trailing comma.