Hi Inderjeet, Michael and Reg
I have to say that I agree with Michael that loads of PR zero backlinks could do a lot more harm than good but, as Reg says, a lot could depend on relevance. In my world of online education I find that very few (20% or less) of sites that are relevant have PR zero - after all a site owner has to do very little to get to the level of PR1. Reg, it would be fascinating to know how you managed to acquire so many links from PR zero sites and then just one excellent site that is PR5 with virtually nothing between. We also need to consider the fact that Google tell us they expect to see a "natural link profile" and 115 links with 113 having PR zero certainly could not be considered "natural". I would think that site is headed for a Google penalty fairly soon!
Inderjeet, if along with your 100 zero PR links you also have a few hundred PR1's and better then I would not worry. On the other hand, if the majority of your inbound links are PR zero then I would be very worried about incurring the wrath of Google!
Hope that helps,
Colin