SEO Mod Creating Duplicate Pages?

Hello Able2Know-

I cannot find many other posts regarding my question, so here goes.

I installed the A2K SEO Static Pages Mod on my phpBB forum a few months ago.

The problem is this: Google now only caches my dynamically generated pages, and they are all listed as "supplemental results". Yahoo, on the other hand, caches only the my static .html pages, and this is where the majority of my traffic is coming from. Neither search engine caches more than 10 percent of all of my pages.

My objective is to get all of my forum posts re-indexed at Google. I am wondering how the problem can be solved.

Are my duplicate pages the cause of the incomplete caching of pages at Google?

Will I have to remove the mod-rewrite feature in order to avoid creating duplicate pages?

Would it be possible to use robots.txt in order to block the dynamically generated pages from being indexed by Google?

I would value some feedback on this-