mkpath() takes a list of directories, so this:

foreach my $dir(@dirs){
mkpath("$to/$dir");
}
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Can be changed to:

mkpath(@dirs);
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But that will only work if $to is prepended to each file name in @dirs. Change your find() to this:

find (sub {push @dirs => $to . '/' . $File::Find::name if -d},$from);
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Unless there's something I'm missing.