It requires perl version 5.6.0 or higher. It sounds like you are using a version that predates that. It should work if you just remove the "our" on the first line.

(update:) then again, tests don't reveal that:

fred$ perl
#!/usr/bin/perl -w
package DB;$sub='main::er';sub BEGIN {$^P=1 unless$sub;
$^P or $_="Not just another perl hack"}sub sub(hack){print
$sub =~ /([^:]+)$/, $", or &$sub} *hacker = \⊂ package
main;sub er {print ",\n"}sub just {for(split' '=>`perldoc`
){print $1 if /(\w{4})\d\w/;}}sub hack {print "hacker"}sub
another { seek DATA, 0, 0;print +(/(\w{6})\d/)?'':$1 while
<DATA>;DB::hacker();}sub perl { print }$_ and print "$_\n"
;foreach (qw{just another perl hack}) {$_->();}print "\n";
[download]

(control-D)

Segmentation fault
fred$ perl -v

This is perl, version 5.005_02 built for sun4-solaris-thread
[download]

Weird.