I'm having problems with PayPal Sanbox: I can set it up OK, but when I try to link it to my PayPal Developer Account i Get the error message 'This sanbox account is linked to another developer account'.
As sandbox account uses fictional emails. I would simply advise you to create an account in https://developer.paypal.com (section Sandbox> accounts) and create a test account from scratch (for example testdma2386@testpayment.com) and use this new one from now on for your tests.
