Google thinks my index pages are duplicates

Does this cause a duplication penalty?

[Vec_One]

When I check my site with a site: search, some of the results display only the URL, with no title or description. I'm not 100% sure, but AFAIK, that indicates a page that has been identified as a duplicate, or is in some other way unimportant. What concerns me is that I see the same page in two or more results.

The fact that the TBPR is always different leads me to believe that Google treats these as two separate pages. I'm concerned that this might be splitting the PR assigned to some important pages.

The URLs are always a little different.

Example 1
[widget.com...]
[widget.com...]

Example 2
[widget.com...]
[widget.com...]

This site got whacked on Sept 22, so I'm looking for reasons. Can anyone who knows more than I do (pretty much anyone) tell me whether this is a problem or not?

Thanks!

[Brett_Tabke]

It is fairly common to have happen. Put in a redirect to the one you want from the one you don't want.

[brakkar]

I was aware about the www w/o problem , but didn't knew this could hapen with / and index files.

So how to have no www, /index.php; no / all redirect to [site.com...]

Thanks,
Brakkar