@line = parse_line($ln) # this will parse the line using substr and save each value in array.

if (exists $File2{$line[3]} ) {
     print "Found the match ",Dumper($File2{$line[3]}),"\n";
} else {
     print "Could not find the match \n";
}

# Tried the following and it does not work either :
if (exists $File2{"$line[3]"} ) {
     print "Found the match ",Dumper($File2{"$line[3]"}),"\n";
} else {
     print "Could not find the match \n";
}