recognizing valid text file variables

[sVanderbutte]

what i'm trying to do is be able to allow a user to specify a text file containing variables through an input box, and flash be able to default to variables if the text file is not found. for instance, if a user input "file.txt", and there was no such file, then flash could display a 'file not found' or whatever. what i currently have on a button
is similar to this:

on(release){
filename = inputBox;
input = (inputBox + ".txt"
if(input == ".txt&quot{
var1 = x;
var2 = x2;
var3 = x3;
gotoAndPlay("wherever"
}else{
_root.loadVariables(input, _root);

gotoAndPlay("wherever"
}
}

i basically need a: if (file != true) kinda thing.

thanks in advance