is there such thing as PR penalty?

Bring some Related links...... and update your content....... Optimize your Rss..... Thats that i did..........

 

Yes there is. I purchased some old domains with PR as high as 7 and as soon as Google discovered different content the PR dropped to 0.

 

it could be a bad neighbourhood for example you may be linking ti bad sites such as link farms or suspected of buying links by getting links for sites not in your niche

 

It happens rarely. If google finds something illegal in the works then only one gets penalty.

 

I dont think you should worry about it but instead keep working the promotion of your site since you already have sunk lots of work into it

 

Dont worry about it.
They are waving to high and low .Keeping high page rank is some lucky

 

that gets the point --they are not so matched foe most of the time
it is an indication