diff --git a/ser.cc b/ser.cc
index 03d4bb7..76e1217 100644
--- a/ser.cc
+++ b/ser.cc
@@ -188,7 +188,7 @@ 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 %lu bytes for timestamps\n",
-	    sizeof(header.DateTime) * NumberOfTimeStamps);
+	    sizeof(header.DateTime) * (long)NumberOfTimeStamps);
     return -1;
   }
 
@@ -246,13 +246,13 @@ int SER::appendFrame(void *data) {
     NumberOfTimeStamps *= 2;
     if((TimeStamps = (int64_t *)realloc(TimeStamps, sizeof(header.DateTime) * NumberOfTimeStamps)) == NULL) { 
       fprintf(stderr, "Error: failed to re-allocate %lu bytes for timestamps\n",
-	      sizeof(header.DateTime) * NumberOfTimeStamps);
+	      sizeof(header.DateTime) * (long)NumberOfTimeStamps);
       return -1;
     }
   }
   
   /* save timestamp for this frame */
-  TimeStamps[FramePointer++] = currentDateTime();
+  TimeStamps[FramePointer++] = currentDateTimeUTC();
   return 0;
 }
 
@@ -344,7 +344,7 @@ void * SER::allocFrame(void) {
   
   /* Try allocating new frame data. */
   if((Frame = malloc(FrameSize)) == NULL) {
-    fprintf(stderr, "Error: failed to allocate %lu bytes for frame\n", FrameSize);
+    fprintf(stderr, "Error: failed to allocate %lu bytes for frame\n", (long)FrameSize);
     return NULL;
   }
   return Frame;
@@ -430,10 +430,10 @@ int32_t SER::getNumberOfFrames(void) {
  */
 int64_t SER::setDateTime(void) {
 
-  int64_t hundred_nano_seconds = currentDateTime();
+  int64_t hundred_nano_seconds = currentDateTimeUTC();
 
-  header.DateTime = hundred_nano_seconds;
-  header.DateTimeUTC = hundred_nano_seconds + differenceLocalUTC();
+  header.DateTimeUTC = hundred_nano_seconds;
+  header.DateTime = hundred_nano_seconds + differenceLocalUTC();
   return header.DateTime;
 }
 
@@ -448,14 +448,13 @@ int64_t SER::setDateTime(void) {
   maximum value represents 100 nanoseconds before the beginning of
   January 1 of the year 10000.
 */
-int64_t SER::currentDateTime(void) {
+int64_t SER::currentDateTimeUTC(void) {
 
   int64_t hundred_nano_seconds;
   struct timeval current_time;
-  struct timezone current_zone;
 
   /* get time since 01.01.1970 00:00 */
-  gettimeofday (&current_time, &current_zone);
+  gettimeofday (&current_time, NULL);
   hundred_nano_seconds = (62135596800L + current_time.tv_sec) * 10000000L +
     current_time.tv_usec * 10L;
   return hundred_nano_seconds;
@@ -486,5 +485,5 @@ int64_t SER::differenceLocalUTC(void) {
 
   fprintf(stdout, "Debug: difference between local time and UTC is %ld hours\n",
 	  (loc_ts - gmt_ts) / 3600);
-  return ((int64_t)gmt_ts - (int64_t)loc_ts) * 10000000L;
+  return ((int64_t)loc_ts - (int64_t)gmt_ts) * 10000000L;
 }
diff --git a/ser.h b/ser.h
index d327195..cbd2628 100644
--- a/ser.h
+++ b/ser.h
@@ -105,7 +105,7 @@ class SER {
   int32_t getNumberOfFrames(void);
   void setNumberOfFrames(int32_t);
   int64_t setDateTime(void);
-  int64_t currentDateTime(void);
+  int64_t currentDateTimeUTC(void);
   size_t getFrameSize(void);
   
   int setFile(char *);