Source Problem

[Fun4Kids 0]

I have a error, i compile my source and i have this error: In file included from ../../libthecore/include/stdafx.h:141:0,
                 from stdafx.h:9,
                 from char_item.cpp:1:
../../libthecore/include/utils.h:143:58: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define _countof(_Array) sizeof(*__countof_helper(_Array))
                                                          ^

gmake: *** [OBJDIR/char.o] Error 1
gmake: *** Waiting for unfinished jobs....
 

Sorry for my bad language, can u help me??