Plot in function

Hello,

I am a R beginner and I have a question about a litte function I found. 
Here is the code:

# Gambler's Ruin Problem.
# seed capital:                k
# rounds:                      n
# probability of success:                  p
# number of trials:             N
# graphical output (yes/no): draw
# Wait for new graphic (yes/no):   ask

ruin<- function( N = 1, n = 10, k = 1, p = 1 / 2,
                draw = FALSE, ask = FALSE ){
  if(draw)
    par( ask = ask )
  r <- 0
  for( i in 1:N ){
    x <- k + cumsum (sample( c(-1, 1),replace = TRUE, n,prob = c(1-p, p)))
    if( min(x) <= 0 ){
      r <- r + 1
      if(draw)
        ruin.plot( k, x, col = "red",main = paste(i, "th trial: ruin!" ) )
    }
    else if(draw)
           ruin.plot( k, x, main = paste( i, "th trial: no ruin" ),ylim =
c( 0, max(x) ) )
  }
  return(r / N)
}

Now I want to start it with for example
"ruin(N=100,n=1000,k=50,draw=TRUE,ask=TRUE)" but i received the message,
that there is an unused argument: (col = "red",main = paste(i, "th trial:
ruin!" ) ).
What is wrong with the code?

ruin(N=100,n=1000,k=50,draw=TRUE,ask=TRUE)