diff -urN Performous-0.6.1-Source.old/cmake/Modules/FindAVUtil.cmake Performous-0.6.1-Source/cmake/Modules/FindAVUtil.cmake
--- Performous-0.6.1-Source.old/cmake/Modules/FindAVUtil.cmake	2012-05-16 13:44:26.112930173 +0200
+++ Performous-0.6.1-Source/cmake/Modules/FindAVUtil.cmake	2012-05-16 13:56:10.229914635 +0200
@@ -25,9 +25,15 @@
       if(EXISTS "${AVUtil_INCLUDE_DIR}/${suffix}avutil.h")
         set(AVUtil_INCLUDE "${suffix}avutil.h")
       endif(EXISTS "${AVUtil_INCLUDE_DIR}/${suffix}avutil.h")
+      if(EXISTS "${AVUtil_INCLUDE_DIR}/${suffix}mathematics.h")
+        set(AVUtilMath_INCLUDE "${suffix}mathematics.h")
+      endif(EXISTS "${AVUtil_INCLUDE_DIR}/${suffix}mathematics.h")
     endif(NOT AVUtil_INCLUDE)
   endforeach(suffix)
 
+  if(NOT AVUtilMath_INCLUDE)
+    message(FATAL_ERROR "Found mathematics.h include dir, but not the header file. Perhaps you need to clear CMake cache?")
+  endif(NOT AVUtilMath_INCLUDE) 
   if(NOT AVUtil_INCLUDE)
     message(FATAL_ERROR "Found avutil.h include dir, but not the header file. Perhaps you need to clear CMake cache?")
   endif(NOT AVUtil_INCLUDE)