This probably isn't contributing to your problem, but one thing that jumps out at me as looking a little funny is this:

$isdir =~ 1
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Essentially, that will evaluate to true if $isdir contains 1 anywhere in it. So 1, 121, 212, 00111 would all evaluate to true in that context. I just never see the binding operator (=~) being used to bind a scalar to a literal digit instead of a regexp, but it works the same as /1/. The only reason I bring it up is that by dropping the m//, it leads me to wonder if you expected the regexp behavior that you're getting.

Maybe you meant to use '==' or 'eq', or '=~ /1/' (for clarity).