I'm not sure where the error is occuring..

I'm getting the following message when I hit the submit button:

    The parameter 'address' cannot be an empty string. Parameter name: address

I've added in the smtp settings for the site in the web.config file and put in a recipient for the email, but can't seem to find any reference to a field called address.

Have I not configured something properly in the form or is it IIS?

Any help'd be much appreciated!

Thanks

Tom