I'm using the Events module, and will be charging to enroll for certain events.  I'm using paypal sandbox to test this functionality.  I set up a seller account and a buyer account.  In DNN I set up the paypal seller account email address in the Event Module Enrollment Settings.  I also set the paypal seller account email address in the Enrollment section when creating a new event.

When I log into DNN as a normal user, click on the event, click on enroll, and then click purchase i am taken to the paypal sandbox site.  The transaction works fine if I then log in to paypal using my test buyer account, and proceed with the purchase.

I would also like to be able to test the "Don't Have a PayPal Account?" option, where a person can pay with a credit card without having to sign in to paypal.  I input a test credit card number, and a valid address and input all the other information, but paypal gives me an error..."Some information is incorrect or missing. Please correct your entries and try again."  It doesn't say what information is incorrect.  After browsing the paypal forums, It appears I'm doing everything correctly.

I was thinking that maybe DNN was passing some variables to paypal that paypal is comparing to the information I'm typing in.  Like the email address or something, and when they don't match I get the error.  If anyone has any information on this, that would be awesome.  Thanks