Hi
I even tried by using the exact code which is shown in following article
http://www.advancedcustomfields.com/resources/how-to/create-a-front-end-form/
but still Add Image button gives same error
I did one small test I tried by removing header, and I found that now I can see two options near Add Image button – (Remove,Edit) these buttons are not getting shown when we use header so some thing issue with js files if u required I can give wp login details and cpanel access
http://ezwebstore.in/health/add-new-service/
Thanks