Hi, I've bought and updated b2jcontact onmy site but It doesn't allow me to add fields properly....

I got this error in the console:

VM598:formatted:1

Uncaught SyntaxError: Unexpected token \ in JSON at position 1
at JSON.parse ()
at Object.success (index.php?option=com_b2jcontact&view=loader&filename=script&type=js:36)
at j (jquery.min.js:2)
at Object.fireWith [as resolveWith] (jquery.min.js:2)
at x (jquery.min.js:5)
at XMLHttpRequest.b (jquery.min.js:5)
success @ index.php?option=com_b2jcontact&view=loader&filename=script&type=js:36
j @ jquery.min.js:2
fireWith @ jquery.min.js:2
x @ jquery.min.js:5
b @ jquery.min.js:5

any Ideas?