Index: src/vortex_thread.c
===================================================================
--- src/vortex_thread.c	(revision 3242)
+++ src/vortex_thread.c	(working copy)
@@ -212,6 +212,8 @@
 	return true;
 }
 
+#define CLOSE_WIN32_HANDLE(X) if(!X) {} else{ CloseHandle(X); (X) = NULL; }
+
 /** 
  * @brief Wait for the provided thread to finish, destroy its
  * resources and optionally release its pointer.
@@ -244,7 +246,7 @@
 		break;
 	}
 	
-	CloseHandle (thread_def->handle);
+	CLOSE_WIN32_HANDLE (thread_def->handle);
 	axl_free (thread_def->data);
 	if (free_data) 
 		axl_free (thread_def);
@@ -336,7 +338,7 @@
 
 #if defined(AXL_OS_WIN32)
 	/* close the mutex */
-	CloseHandle (*mutex_def);
+	CLOSE_WIN32_HANDLE (*mutex_def);
 #elif defined(AXL_OS_UNIX)
 	/* close the mutex */
 	if (pthread_mutex_destroy (mutex_def) != 0) {
@@ -393,7 +395,7 @@
 
 #if defined(AXL_OS_WIN32)
 	/* unlock mutex */
-	ReleaseMutex (*mutex_def);
+	if( *mutex_def ) ReleaseMutex (*mutex_def);
 #elif defined(AXL_OS_UNIX)
 	/* unlock mutex */
 	if (pthread_mutex_unlock (mutex_def) != 0) {
@@ -739,10 +741,10 @@
 
 #if defined(AXL_OS_WIN32)
 	/* close semaphore */
-	CloseHandle (cond->sema_);
+	CLOSE_WIN32_HANDLE (cond->sema_);
 
 	/* close the event */
-	CloseHandle (cond->waiters_done_);
+	CLOSE_WIN32_HANDLE (cond->waiters_done_);
 
 	/* delete critical section */
 	DeleteCriticalSection (&cond->waiters_count_lock_);