diff --git a/ser.cc b/ser.cc
index a07f506..03d4bb7 100644
--- a/ser.cc
+++ b/ser.cc
@@ -32,6 +32,9 @@ SER::SER() {
   FileDesc = NULL;
   Frame = NULL;
   FramePointer = 0;
+  FrameSize = 0;
+  NumberOfPlanes = 0;
+  BytesPerPixel = 0;
   Reading = 1;
   NumberOfTimeStamps = 0;
   TimeStamps = NULL;
@@ -184,7 +187,7 @@ int SER::writeHeader(void) {
   }
   /* allocate some memory for the upcoming timestamps */
   if((TimeStamps = (int64_t *)malloc(sizeof(header.DateTime) * NumberOfTimeStamps)) == NULL) {
-    fprintf(stderr, "Error: failed to allocate %d bytes for timestamps\n",
+    fprintf(stderr, "Error: failed to allocate %lu bytes for timestamps\n",
 	    sizeof(header.DateTime) * NumberOfTimeStamps);
     return -1;
   }
@@ -242,7 +245,7 @@ int SER::appendFrame(void *data) {
   if(FramePointer >= NumberOfTimeStamps) {
     NumberOfTimeStamps *= 2;
     if((TimeStamps = (int64_t *)realloc(TimeStamps, sizeof(header.DateTime) * NumberOfTimeStamps)) == NULL) { 
-      fprintf(stderr, "Error: failed to re-allocate %d bytes for timestamps\n",
+      fprintf(stderr, "Error: failed to re-allocate %lu bytes for timestamps\n",
 	      sizeof(header.DateTime) * NumberOfTimeStamps);
       return -1;
     }
@@ -341,7 +344,7 @@ void * SER::allocFrame(void) {
   
   /* Try allocating new frame data. */
   if((Frame = malloc(FrameSize)) == NULL) {
-    fprintf(stderr, "Error: failed to allocate %d bytes for frame\n", FrameSize);
+    fprintf(stderr, "Error: failed to allocate %lu bytes for frame\n", FrameSize);
     return NULL;
   }
   return Frame;