Hi,
I'm having my own site. I've checked its page rank and it is shown 4 (some pages are having 3) from all the datacentres of Google, and many other websites.
But I'm afraid to see "Suspicious Page Rank" comments in lots of websites, while checking the page rank. Some are saying, "We cannot determine the page rank of this site", though all of them are showing PR 4 at the same time in results.
What does it implies. Can any SEO expert check this and tell me the reason. I'll be glad to to know some suggestions to resolve this problem.

For assistance, I'm providing my sites' URLs here:
Home Page (Page Rank 4)
Order Page (Page Rank 3)

Don't worry about it ... The PR that the Google toolbar spits out has been widely known within the SEO industry as completely stale / old / just plain flat out wrong data for about a year now. It's Google's way of making sure that we don't "buy pagerank" or do all of that black hat stuff.

Thank you Mam for your reply. So, are you assuring that it's not a problem at all? Can you please tell me, when or how this unwanted comments will disappear?

It is not a problem at all - whatever the Google PR toolbar says. Don't focus on it. Instead, sign up for Google's Webmaster Tools at www.google.com/webmasters/ and it will tell you the truth about how your site is doing in Google.

Correct don't worry on PR and least bother for same.