open FILE problem

[Jennifer Pan]

Hello all,  I came across this problem opening up files that are fed in
from command line using "ls". I do not know why this script did not
work. Appreciated any input. 

#!/usr/local/bin/perl

# I am trying to feed all the files in this directory to do text
processing and save the processed txt into an #output called outout.txt

while ($LINE = <STDIN>) {
        chomp $LINE;
        open (AFILE, "$LINE") or die ( "cannot open $LINE");    
        open X, ">>output.txt";
        while ($LINE1 = <AFILE>) {
                $LINE1 =~ s/^\s*//;
                print X "$LINE1";
        }
        close X;
        close AFILE;
}

at prompt I typed
ls *.txt | perl format.pl

it never worked!!!! it always "die" cannot open $LINE. I don't
understand why

thanks

-jen