Had you done use strict and use warnings you'd have gotten helpful diagnostics about leaving off the $ from $i in the for loop. That aside, a more natural way of writing that (presuming you've left out whatever processing you're doing for each file) would have been:

for my $file ( @array ) {
  open( FILE, $file ) or die "Can't open '$file': $!\n";
  ## Do something with the contents of $file
  close( FILE );
}
[download]

I assume you mean something more like this:

use strict;
use warnings;

my @array = qw/ foo bar baz blah /; 

for(my $i = 0; $i < @array; $i++) {
    print "$i $array[$i]\n";
}
[download]

use strict;
use warnings;

my @array = qw/ foo bar baz blah /; 

foreach my $filename (@array) {
    print "$filename\n";
}
[download]

Please notice I added use strict; and use warnings these are a MUST when you are learning perl.

Also notice I did not use the actual open - I simplified to find the real root of the problem