Hi,  I am trying to purchase a voucher but continue getting errors. After I select the Register button and select;

- 'Use your current Salesforce login....' option, after entering my username and pw, I am returned to the Login page.  Should I be able to login with a developer account ID? I currently only have a developer account.

- If I select 'Continue as a guest', I am able to see my shopping cart, enter payment and billing info, but when I select Confirm and Enrol, I receive an error message 'One or more fields in the form are missing or invalid'

I have verified all fields are completed (tried many times), cleared my cache and tried again, but am still unable to complete the purchase.