There are still some PTC sites using PayPal as payment method, one of them is WordLinx which has already been around for 5 years. NeoBux, TheClickers and most of the Aurora PTC sites also use PayPal. But I have never heard of a site using PayPal instant payment. As far as I know, it cannot be done, but I might be wrong.
Anyway, I see this site uses Gen2Script (so far from NeoBux, although the default design is made to look like NeoBux). This kind of script is usually loaded with bugs, so expect many problems here. As of now, the problem is in the referral click which are not recorded. You can see the members complain about it in their forum.
Btw, paramitha, what are the exact click rate for this site. I ask because it says up to, so usually, it's not the real value for standard members.