I'm not following the entire piece of code, but I'd like to point out that that big built-up regex probably isn't what you want. You may want to think about building it up with the qr operator, that way you can embed your comments much more cleanly, e.g.:

my $pattern = qr/
  S[s|p]           # match the link label
  (?:[\w\*]{1,2})* # match any optional subscripts
  :(\d+):          # match number of the word
  (\w+(?:\.\w)*)   # match and save the word itself
  [^\)]+           # match other stuff within parenthesis
  "(rock[s|ed]*).v"# match and store verb
  [^(?:O.{1,2}:    # don't match objects
  \d+\:\w+(?:\.\w)*)]*\)
/xm;
[download]

And then I suggest running the resultant object through something like YAPE::Regex::Explain. I don't think this is what you really want.

e.g., [s|p] matches s, |, or p. Not "s or p". Or what you have for "don't match objects" displays a common misconception about how the square brackets work. The Y::R::E tool will help you understand what you have there.

Hope this helps - good luck!