Try calling them and asking why you were not accepted, maybe if you amke their requested changes they will reconsider you.
You just don't meet their requirements that's all, it could be a number of things that they expect, like traffic, look, etc. Try applying with another site if you have another one.
There is no way PR can be a factor in YPN accepting you or not, there have got to be other reasons... try giving them a call, but i doubt if that would work.. You can apply with another site and try out your luck, you never know...
I don't think it would be against the TOS to apply again, unless it is stated. You should ideally try with another site (unless in your rejection email it is stated that you can never apply again....which i don't think would be the case), not exactly sure how the ypn sysyem works, since i'm not from the US and don't have an a/c