I'm not sure if it's just me, but for some reason pagerank isn't showing for any websites. I'm using a firefox pagerank plugins, AND I have the google toolbar, and all pageranks show N/A. Even websites that ping the google server to show pageranks show errors. Are you guys getting the same?
I use search status and have noticed it loads that information a lot faster than the google toolbar, it might be worth checking out.
I use the Live PageRank FireFox addon. Today I was having issues too. It wouldn't show the PR for many sites until I clicked on the PR bar. Try that meamrussian.
There may be a bug in your browser, I've been using the firefox toolbar everyday to check pr and it's been working fine for me.
Search status is a great tool for checking pr. But if you don't want a plug-in, you can check this link prchecker. Re-installing the plug-in would be the best solution for your problem.
It looks like something is happening. I have n/a for all my internal pages today in both firefox extensions and IE Google Toolbar. I am white hat all the way so I'm not worried about penalties. Plus my serps are not affected, actually in the past 30 days I have a 30% spike in Search Engine Traffic.