I am tesing the free version latest edition. I have sandbox paypal accounts and have been testing IPN verification.
 
I had shopping card set to NOT require registration to place and order and passwords were NOT encrypted.
 
The cart was working fine with IPN validation working.
Confirmation page was showing confirmed orders and emails set and amin showed orders ok.
 
I changed cart settings to encrypt passwords and require registration before ordering.
 
Made another test order and confirmation page now shows error can't find order information.
 
Admin area shows the order as validated, emails are set but for some reason the confirmation page is not showing a validated order!
 
I tried changing the cart back to alow non members orders but I still get an error on the order validation page.