--- a/src/Types.hh	Mon Dec 08 21:15:52 2008 +0000
+++ b/src/Types.hh	Mon Dec 08 21:18:08 2008 +0000
@@ -32,11 +32,11 @@
 /**
  * A time interval, measured in real milliseconds
  */
-typedef unsigned long TimeMS;
+typedef signed long TimeMS;
 
 /**
  * Abstract tick count, defined as a number of Timer::interval's against real time
  */
-typedef uint32_t TickCount;
+typedef int32_t TickCount;
 
 #endif