Remove null geometries.a) Follow the method recommended in KB 32295 “HowTo: Update a NULL geometry using ArcMap”<a href="http://support.esri.com/index.cfm?fa=knowledgebase.techArticles.articleShow&d=32295" target="_blank">http://support.esri.com/index.cfm?fa=knowledgebase.techArticles.articleShow&d=32295</a>b) Remove Null geometry using the Repair Geometry tool.