Show us the actual code you tried and tell us what issue you saw. $counter = 1 & ++$counter is rather unlikely code and probably doesn't do anything like what you expect, although it's hard to tell what you expect.

Don't use the C style for loop. Instead use:

for my $counter (1 .. 9) {
    ...
}
[download]

which is much clearer and a lot harder to get wrong.