I have now upgraded to version 2.1.0, but the same problem continues.

As per your question, no. No unusual characters, except for things like * in the description field in the "Form Display" column. This colums holds descriptive information for the fields being filled out. I use the * in the description as a way of telling which field is required when the form is being viewed in the admin.

I did post the error message in my previous message. The error is one that says that "Field x cannot be left blank" when submiting the registration form. But as I said, the error occurs even if the fields are all filled out.

So, as for now, I have de-activated all the required fields, but I would appreciate being able to require some fields so I can collect some data about the people signing up.

Thanks.