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) in C:\PROJEKTE\DynamicWeb\beta.weber.de\Application\Extenders\WeberProductExtender.cs:line 41
   at CustomModules.Extenders.WeberProductExtender.ExtendTemplate(Template Template) in C:\PROJEKTE\DynamicWeb\beta.weber.de\Application\Extenders\WeberProductExtender.cs:line 14
   at Dynamicweb.eCommerce.Frontend.Renderer.RenderProductTemplateExtenders(Product Product, Template Template)
   at Dynamicweb.eCommerce.Frontend.Renderer.RenderProduct(Product Product, Boolean ExtendedProperties, Template Template, Int32 loopCounter, Boolean renderRelated)
   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)