Sandbox cannot add funds
paypal-sandbox
Solution
You have to login at https://developer.paypal.com with your developer account and then go to Applications->Sandbox Accounts->Create Account, the 5th field is "PayPal balance" here you can put any amount you want to your test account.
Problem
I'm having grief with the new PayPal Developer site and Sandbox. I've created a personal account in the Developer but the funds I added are not showing up. I read a forum post that you had to add funds via the Sandbox login but it won't let me add funds either. Phil