I've got a form that was sending to paypal, and accepting a payment in the sandbox, but was not registering a user.
After searching the forums, I found that someone had the same problem, cause by having HTML in a required field. I removed the link in that required field.
Now the form registers the user, but does not send to paypal. The form just disappears, and leaves me on the same page.
This error is on 2 forms that are identical aside from the subscription amount,