Index: trunk/psModules/src/imcombine/pmSubtractionStamps.c
===================================================================
--- trunk/psModules/src/imcombine/pmSubtractionStamps.c	(revision 33433)
+++ trunk/psModules/src/imcombine/pmSubtractionStamps.c	(revision 33435)
@@ -1208,5 +1208,13 @@
 	// XXX this is somewhat arbitrary...
 	if (source->psfMagErr > 0.05) continue;
-	if (fabs(source->psfMag - source->apMag) > 0.5) continue;
+        if (isfinite(source->apMag)) {
+            if (fabs(source->psfMag - source->apMag) > 0.5) continue;
+        } else if (isfinite(source->apMagRaw)) {
+            if (fabs(source->psfMag - source->apMagRaw) > 0.5) continue;
+        } else {
+            // XXX: Should we carry on or drop this source?
+            // drop it for now
+            continue;
+        }
 
         if (source->modelPSF) {