Anyway, back to the original question, the problem might be that you are on a 64bit server - is this your case? What does echo PHP_INT_SIZE PHP: tells you? If it's > 4 you are on a 64bit machine and you need to slightly change the pagerank class
http://www.google.com/search?hl=en&q=pr+check&btnG=Google+Search first two: http://www.prchecker.info/check_page_rank.php http://www.checkpagerank.com/ and they have been around for a while now they don't ban sites... rumors again