Index: trunk/ippTools/src/pxinject.c
===================================================================
--- trunk/ippTools/src/pxinject.c	(revision 10115)
+++ trunk/ippTools/src/pxinject.c	(revision 10231)
@@ -126,5 +126,11 @@
             return false;
         }
-        dateobs = psTimeFromISO(dateobsStr, PS_TIME_UTC);
+        // pass through NULL as this is an optional field
+        if (dateobsStr) {
+            dateobs = psTimeFromISO(dateobsStr, PS_TIME_UTC);
+        } else {
+            dateobs = NULL;
+        }
+
     }