Pagerank checker got temp blocked, Need Help to Fix

I need someone who can help me to fix my pagerank checker script, I have written a PR checker which checks google pagerank, fake PR, alexa rank and backlinks. but now I got a problem with the PR checking part, it seems like that my site receives lots of traffic and too many checking requests have been sent to google, and the requests got temporarliy blocked, therefore, no results can be returned, I dont know how to fix it, I have tried to limit the checking interval to 10 seconds, but still dont work. I have seen similar tool working well on [login to view URL] and [login to view URL] even though they have received lots of checking request, I need someone who know how to get it work, thanks. Pls make sure you are able to communicate via MSN. I will give my sites' URL in private msg.