Error on localhost

My problem is that when I try to upload an image to a custom field that I have created before with toolset types plugin , wordpress is showing me always this error: “Please enter a valid URL address pointing to the image file.”
I think that is a bug of the plugin because when I change the url and I put a real URL it works well.

Is not working with : ‘http://localhost/….’
Working with: ‘http://example.com/…’

Please solve this issue, thanks a lot.