Citroen Chili Garnalen

An error occured while attaching module (Dynamicweb.Frontend.Content)

System.NullReferenceException: Object reference not set to an instance of an object.
   at CustomModules.Extenders.WeberProductExtender.RenderGalleryTitles(Template Template)
   at CustomModules.Extenders.WeberProductExtender.ExtendTemplate(Template Template)
   at Dynamicweb.eCommerce.Frontend.Renderer.RenderProductTemplateExtenders(Product Product, Template Template)
   at Dynamicweb.eCommerce.Frontend.Renderer.RenderProduct(Product Product, Boolean ExtendedProperties, Template Template, Int32 loopCounter, Product relationMasterProduct)
   at Dynamicweb.eCommerce.Frontend.Renderer.RenderProduct(Product Product, Boolean ExtendedProperties)
   at Dynamicweb.eCommerce.Frontend.Frontend.RenderProduct(Product prod)
   at Dynamicweb.eCommerce.Frontend.Frontend.EcomRender()
   at Dynamicweb.eCommerce.Frontend.Frontend.GetContent()
   at Dynamicweb.Frontend.Content.getModule(DataRow& ParagraphRow)