prblem with NA

Hi all

I have a data set with the total number of columns =ncol, and the total
number of rows=nrow. I am trying to loop over the values and id the value is
less than or equal to 100 to be changed to 1. if the value is greater than
100 , to be changed to 0. if NA , let X[i,j]=NA. I ran into a problem where
if one row in my data set had all values =NA, then the program does not
continue working past that row!  

At some point I get the following error message:

?Error in if (data [i, j] <= 100) { : missing value where TRUE/FALSE needed?

Here is the program 

data<-read.table("fileName.txt", header=F, sep='\t')

X=data
for(i in ncol)
{
for(j in nrow)
{
if(data[i,j]<=100) {X[i,j]=1}
if(data[i,j]>100) {X[i,j]=0}

if(is.na(data[i,j])) {X[i,j]=NA}
}
}