...I'm suspecting that there is a problem in the manner that I am calling the subroutine.

Yep. If you rename that $i variable to $subref, it will become apparent what you can do next.
The other thing to remember is that you can't embed a function call directly in a string. You can assign the result to a variable (scalar or array) and embed that; or you can pass multiple arguments to print(), as I do below.

  for my $key ( %HoL ) {
    for my $subref ( @{ $HoL{$key} } ) {
      print "$key -> ", &{$subref}, "\n";
    }
  }
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(P.S. -- whitespace good. :-)

jdporter
The 6th Rule of Perl Club is -- There is no Rule #6.