Perhaps it would help if you tried to give a brief description of what your grammar is supposed to handle. Apart from that, it looks like the initial part of your grammar goes wrong in the trace, and there are some likely suspects in the first rule:

• there is a strandard single-quote character just before $item[2]
• you're using curly braces, which I think are supposed to be used for bracketing snippets of perl code, but there is no perl code inside them
• there are parens around a set of "|"-conjoined elements, then some other stuff ouside the parens, which may just be uninterpretable.

I'm already way over my head here -- to date, I've only looked at the PRD man page (I've never written code to use it), and have used lex/yacc only rarely, in a previous life, so one or more of the above items may be a false lead.

Have you arrived at this grammar via a series of preliminary and intermediate steps, building it up from pieces that you have tried successfully? Or have you just created the whole thing from scratch, without testing any single component by itself, and you're now trying to debug the whole thing at once?

Naturally, I'd recommend the former approach if you haven't tried it. Start with something small and constrained (but relevant) -- feed it with equally constrained input if that helps -- then build up incrementally; when you hit a snag, show us what you have, indicating which parts are known to be working, and what incremental piece introduced the snag.

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