Index: /trunk/ppMerge/src/ppMergeCombine.c
===================================================================
--- /trunk/ppMerge/src/ppMergeCombine.c	(revision 13938)
+++ /trunk/ppMerge/src/ppMergeCombine.c	(revision 13939)
@@ -304,4 +304,5 @@
             for (int i = 0; i < filenames->n; i++) {
                 pmFPA *fpaIn = data->in->data[i]; // Input FPA
+		if (!fpaIn) { continue; } // was not a valid input file
                 pmChip *chipIn = fpaIn->chips->data[view->chip]; // Input chip
                 pmCell *cellIn = chipIn->cells->data[view->cell]; // Input cell
@@ -324,4 +325,5 @@
         for (int i = 0; i < filenames->n; i++) {
             pmFPA *fpaIn = data->in->data[i]; // Input FPA
+	    if (!fpaIn) { continue; } // was not a valid input file
             pmChip *chipIn = fpaIn->chips->data[view->chip]; // Input chip
             pmChipFreeData(chipIn);
@@ -343,4 +345,5 @@
     for (int i = 0; i < filenames->n; i++) {
         pmFPA *fpaIn = data->in->data[i]; // Input FPA
+	if (!fpaIn) { continue; } // was not a valid input file
         pmFPAFreeData(fpaIn);
     }