Hi lmrntx,
Thanks for contributing to our forum. Our system is set up such that all users must have an automatic payment method on file in order to use a paid subscription plan. However, if you would like to prevent your automatic payment method from being charged, you can always make a manual payment for your outstanding fees each month before your automatic billing date.
As the warning you mentioned indicates, in order to prevent this message from continuing to be displayed within your account, you will need to create a new Paypal billing agreement or place a credit card on file which can be used for automatic monthly payments.
If you mouse over the "My Account" tab within your account and select the "My Payment Method" option, you will find the option to do either of these things on the ensuing page.
I hope this clears things up. If you need any further assistance with your account, please feel free to contact our Customer Support team by mousing over the "My Account" tab within your account and selecting the "File Support Case" option.
-Mike
[edited to bold text based on user request]