As Hellas pointed out, PaRaMeter indeed does have flaws as it sometimes doesn't recognize pages which have PR.
try also seoquake - in google -->
site: command + autopager(plugin for ff) --
set google preference to 100 results -
scroll down X number results ( few thousands if applicable) -->
click external link in seoquake see all info not just pr (other info can be turned of ) in a neat excell exportable format
cons: only indexed pages but since your checking for pr no issue there
pros: much more flexible then any other purpose built app and can be used for many different things..
Or you can just create a sitemap with all of your posts then use this, Webmaster Tools, works for me :D
Google only shows the PR for pages which are indexed. You do not need any tool to know PR for each webpage.