PR - "...not ranked" for index and main pages

The PR: 1 day ago, it disappeared

[whichcome]

Hello

Yesterday: the PR for index page is "not ranked". The rest of pages Google bar ranks as usually. Today - the same situation.
Could somebody explain what this is? Are encountering the same other sites?
The site is found in the SERPs but the visitor’s number from Google and Yahoo is decreasing.

[gypsychild]

With lots of sites I've come across recently the index page isn't ranked - I wouldn't be too concerned unless you've seen a drastic decrease in traffic over some time.