Error while submission

I have completed part 2 of the assignment and am getting the desired output.
But on submitting the code, it shows as the answer is incorrect along with
this message:

function (..., list = character(), package = NULL, lib.loc = NULL, verbose
= getOption("verbose"),
    envir = .GlobalEnv)
Result:  Sorry, your answer was incorrect.

The following is my code for part 2:

complete <- function(directory, idvec = 1:332) {
        df <- data.frame(id = integer(), nobs = integer())
    for (id in idvec) {
        filename <- paste(directory, "/",
                          sprintf("%03d", as.integer(id)),
              5            ".csv", sep = "")
filename <- list.files()
        dat <- rbind(dat, read.csv(filename[id]))
}
str(data)
for (id in idvec)
        {nd <- data.frame(id = id,
                         nobs = nrow(na.omit(dat)))
        df <- rbind(df, nd)
    }
    return(df)

}

I am using R 3.2.1 on a Windows 8 laptop.

How shall I solve this?

Thanks and regards
Nikita