Interest Group field not functioning (not enabled?)

Hi,

I created interest group within a list in MailChimp. But the checkboxes do not function in the form page which I created in wordpress using easy mailchimp extender.

https://cloud.githubusercontent.com/assets/11580917/6763447/56d7a4be-cfb8-11e4-9974-6c126cf894ed.png

In the Error Log, it shows this

https://cloud.githubusercontent.com/assets/11580917/6763448/60741e58-cfb8-11e4-86aa-45be5a59135f.png

I looked into any setting in MailChimp, I cannot find a place to enable or disable the interest group fields. In MailChimp, the interest group field is set to visible.

Anyone could help? Please…