You need to flag that you intend the regex to be multi line with comments using the x modifier. When quoting a regex use the qr operator:

my $regex =qr{
    ^(\w*)?\s         #A comment
    (\w*)?\s          # an other 
    (\w*)?\s          # and again
    (?:([A-Z]*)\s)?   # all the way through
    (\d+)\*           # so that the homicidal psychopath
    (?:([0-9+]+)[>])? # who knows where you live
    ([0-9+]+)\s.      # and will have to maintain this code
    (\d*)             # will think well of you
    }x;

$input=~$regex
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http://http://www.perl.com/doc/manual/html/pod/perlop.html#item_qr for more detail