diff --git a/src/zm.h b/src/zm.h
index 092561378..ad0f89584 100644
--- a/src/zm.h
+++ b/src/zm.h
@@ -17,9 +17,6 @@
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 // 
 
-#if !defined(PATH_MAX)
-#define PATH_MAX 1024
-#endif
 
 #ifndef ZM_H
 #define ZM_H
diff --git a/src/zm_comms.h b/src/zm_comms.h
index 133c0d19f..e93951a85 100644
--- a/src/zm_comms.h
+++ b/src/zm_comms.h
@@ -20,6 +20,7 @@
 #ifndef ZM_COMMS_H
 #define ZM_COMMS_H
 
+#include "zm_logger.h"
 #include "zm_exception.h"
 
 #include <string.h>
diff --git a/src/zm_config.h.in b/src/zm_config.h.in
index f321095df..87a0f2db4 100644
--- a/src/zm_config.h.in
+++ b/src/zm_config.h.in
@@ -20,9 +20,11 @@
 #ifndef ZM_CONFIG_H
 #define ZM_CONFIG_H
 
+#if !defined(PATH_MAX)
+#define PATH_MAX 1024
+#endif
 #include "config.h"
 #include "zm_config_defines.h"
-#include "zm.h"
 
 #include <string>
 
diff --git a/src/zm_exception.h b/src/zm_exception.h
index 83d1ecab1..a02653b88 100644
--- a/src/zm_exception.h
+++ b/src/zm_exception.h
@@ -20,8 +20,6 @@
 #ifndef ZM_EXCEPTION_H
 #define ZM_EXCEPTION_H
 
-#include "zm.h"
-
 #include <string>
 
 class Exception
diff --git a/src/zm_ffmpeg.cpp b/src/zm_ffmpeg.cpp
index b35e211fd..793869e4a 100644
--- a/src/zm_ffmpeg.cpp
+++ b/src/zm_ffmpeg.cpp
@@ -43,10 +43,14 @@ void log_libav_callback( void *ptr, int level, const char *fmt, va_list vargs )
     log_level = Logger::DEBUG1;
   } else if ( level == AV_LOG_DEBUG ) { //48
     log_level = Logger::DEBUG2;
+#ifdef AV_LOG_TRACE
   } else if ( level == AV_LOG_TRACE ) {
     log_level = Logger::DEBUG8;
+#endif
+#ifdef AV_LOG_MAX_OFFSET
   } else if ( level == AV_LOG_MAX_OFFSET ) {
     log_level = Logger::DEBUG9;
+#endif
   } else {
     Error("Unknown log level %d", level);
   }
diff --git a/src/zm_logger.cpp b/src/zm_logger.cpp
index 3ea0c1668..90a2b9aac 100644
--- a/src/zm_logger.cpp
+++ b/src/zm_logger.cpp
@@ -444,6 +444,7 @@ void Logger::closeSyslog() {
 void Logger::logPrint( bool hex, const char * const filepath, const int line, const int level, const char *fstring, ... ) {
   if ( level > mEffectiveLevel ) 
     return;
+  log_mutex.lock();
   char            timeString[64];
   char            logString[8192];
   va_list         argPtr;
@@ -579,6 +580,7 @@ void Logger::logPrint( bool hex, const char * const filepath, const int line, co
       abort();
     exit(-1);
   }
+  log_mutex.unlock();
 }
 
 
diff --git a/src/zm_logger.h b/src/zm_logger.h
index 8e2ab6c9d..f65c5ec31 100644
--- a/src/zm_logger.h
+++ b/src/zm_logger.h
@@ -30,6 +30,8 @@
 #endif // HAVE_SYS_SYSCALL_H
 #include <mysql/mysql.h>
 
+#include "zm_thread.h"
+
 class Logger {
 public:
   enum { 
@@ -82,6 +84,8 @@ private:
   static bool smInitialised;
   static Logger *smInstance;
 
+  RecursiveMutex log_mutex;
+
   static StringMap smCodes;
   static IntMap smSyslogPriorities;
 
diff --git a/src/zm_thread.h b/src/zm_thread.h
index 0c41a93a5..8cdfb892c 100644
--- a/src/zm_thread.h
+++ b/src/zm_thread.h
@@ -20,9 +20,12 @@
 #ifndef ZM_THREAD_H
 #define ZM_THREAD_H
 
+class RecursiveMutex;
+
+
+#include "zm_config.h"
 #include <unistd.h>
 #include <pthread.h>
-#include <unistd.h>
 #ifdef HAVE_SYS_SYSCALL_H
 #include <sys/syscall.h>
 #endif // HAVE_SYS_SYSCALL_H