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I am getting this error 

I have cloned your form and I can see the same error is happening on my cloned form, upon checking the form preferences I found that you're trying to set an image as background, but you're using this url("../../images/brushed.png") repeat scroll center center rgb(153, 153, 153) 

I would suggest you to remove that code and let it empty, and then set an image as background in the Designer, to get the Designer click on the icon shown below, you will find it on the top toolbar in the Form Builder: 

There you can paste the URL to an already uploaded image or upload an image: 

You can also inject this CSS code to your form: 

.form-all{

    border-image: url("Paste the URL to an already uploaded image") repeat scroll center center rgb(153, 153, 153);

}

This guide will help you to inject the code: How-to-Inject-Custom-CSS-Codes

After doing this your form should start working fine, here is the link to my cloned form where after doing this worked as it should: https://form.jotform.com/61465668278975 

Hope this helps.