Aww. :(

Well actually it doesn't matter that much, it could be any variable in its place. The first version just had $**=4; which I thought looked cool, so it stayed. Here's one using $: instead:

  $"="032";($:=++$|)*=4;open+0;sub  #074117115116
   _{$_=<0>;~/.*#(.+)(?{$,.=$+.$"   #097110111116104101114
    ;$:--?_():0})/}_;$,=~s/.$//;    #080101114108
     map{print chr}$,=~/(...)/g     #104097099107101114046010
[download]

My main source of concern with 5.10 was (?{}) in a regular expression, since perldoc says it is experimental and may be changed without notice between releases.

Thanks for the reply though! :)