Hi, i have a Umbraco V4.7.2 with a fresh installation of Contour 1.1.13.2. (Licensed) But when i try to create a new form with for example 1 fieldset and save it, get the following error: "Failed to save form"

In the firebug console get the error: 

POST http://my-site.com/umbraco/plugins/umbracoContour/Designer.asmx/Save 500 (Internal Server Error) ScriptResource.axd:5

Sys.Net.XMLHttpExecutor.executeRequest ScriptResource.axd:5
Sys.Net._WebRequestManager.executeRequest ScriptResource.axd:5
Sys.Net.WebRequest.invoke ScriptResource.axd:5
Sys.Net.WebServiceProxy.invoke ScriptResource.axd:5
Sys.Net.WebServiceProxy._invoke ScriptResource.axd:5
UmbracoContour.Webservices.Designer.Save js:17
UmbracoContour.Webservices.Designer.Save js:40
(anonymous function) umbracoforms.editformpage.eventhandlers.js:37
fireEvent umbracoforms.designsurface.js:21
SaveDesign umbracoforms.designsurface.js:106
SaveDesign umbracoforms.js:1277
onclick editForm.aspx:225

Can anyone help me?

Thanks in advance and sorry for my english.