diff --git a/src/main/java/electrosphere/main/structure/ProjectStructure.java b/src/main/java/electrosphere/main/structure/ProjectStructure.java
index 02896d1..6faabaf 100644
--- a/src/main/java/electrosphere/main/structure/ProjectStructure.java
+++ b/src/main/java/electrosphere/main/structure/ProjectStructure.java
@@ -325,6 +325,11 @@ public class ProjectStructure {
      * @return the id
      */
     private int getFieldId(String bTreeName, String fieldName){
+        //init the map if it doesn't already exist (ie the file doesn't exist)
+        if(existingFieldNameToIdMap == null){
+            existingFieldNameToIdMap = new HashMap<String,Integer>();
+        }
+        //get the id
         String qualifiedName = bTreeName.toUpperCase() + "_" + fieldName.toUpperCase();
         if(existingFieldNameToIdMap.containsKey(qualifiedName)){
             return existingFieldNameToIdMap.get(qualifiedName);