Null check added. Was throwing exception when serializing document or part of document.

DocX/Container.cs

                 }
 
                 XElement body = Xml.Element(XName.Get("body", DocX.w.NamespaceName));
-                XElement baseSectionXml = body.Element(XName.Get("sectPr", DocX.w.NamespaceName));
-                var baseSection = new Section(Document, baseSectionXml) { SectionParagraphs = parasInASection };
-                sections.Add(baseSection);
-
+                if (body != null)
+                {
+                    XElement baseSectionXml = body.Element(XName.Get("sectPr", DocX.w.NamespaceName));
+                    var baseSection = new Section(Document, baseSectionXml) { SectionParagraphs = parasInASection };
+                    sections.Add(baseSection);
+                }
                 return sections;
             }
         }

DocX/Table.cs

             get
             {
                 XElement trPr = Xml.Element(XName.Get("trPr", DocX.w.NamespaceName));
+                if (trPr == null)
+                    return false;
                 XElement tblHeader = trPr.Element(XName.Get("tblHeader", DocX.w.NamespaceName));
                 return tblHeader != null;
             }