Index: branches/pap/psModules/src/objects/pmSourcePhotometry.c
===================================================================
--- branches/pap/psModules/src/objects/pmSourcePhotometry.c	(revision 28498)
+++ branches/pap/psModules/src/objects/pmSourcePhotometry.c	(revision 28534)
@@ -393,4 +393,8 @@
     psImage *mask     = source->maskObj;
 
+    if (!flux || !variance || !mask) {
+        return false;
+    }
+
     for (int iy = 0; iy < flux->numRows; iy++) {
         for (int ix = 0; ix < flux->numCols; ix++) {