I'm having exactly the same problem and with the same version of ZC. Have tried checking my error logs but nothing obvious showed up. will do so again tonight. My problem is clearly at the stage of PP communicating back to ZC after taking the payment. no order shows and no confirmation follows.
have even changed the cmod permissions on the main_ipn_handler to 755 as recommened in another post.
I have checked with my host re the two recommended ports described in the ZC wiki and this is what they said:
Ports 80 and 443 are not open for outbound connections from the server for security reasons. The suggested IP addresses from Paypal have been added to our firewall configuration.
Am i likely to be able to use Paypal with ZC at all in light of that? Can i point Paypal to another file instead or some other kind of workaround? We're only a startup so Paypal is about all we can afford at this stage.
Cheers
Sam