Forums Developers mirc dll mapping isnt working

this is based on xpopup dll mapping with mirc

ive got this at the top

HANDLE mapFile;
LPSTR mapData;
HWND mapHWND;

on dll load function i do

mapFile = CreateFileMapping(INVALID_HANDLE_VALUE, 0, PAGE_READWRITE, 0, 4096, "mIRC");
mapData = (LPSTR) MapViewOfFile(mapFile, FILE_MAP_WRITE, 0, 0, 0);

void mIRCError(const char * data ) {

wsprintf(mapData, "//echo -a %s", data);
SendMessage(mapHWND, WM_USER + 200, 0, 0 );
}

but mIRCError("test");

doesnt work, i dont see it echo in my mirc, can anyone help?