Sending UDP data at a fixed rate

I have a program that I want to use to send UDP data frames at a fixed
rate. Right now, at 25ms between frames about 1 in 10 is delayed by a
few ms. I've used other programs that manage to get this kind of
success at 10ms between frames.

I'm using a multimedia timer (see below) to get my current level of
accuracy. What can I do to improve things?

Thanks,
PaulH

int delay = 25; //25 ms between frames
HANDLE hSendNextFrame = CreateEvent( NULL, FALSE, FALSE, NULL );
MMRESULT mmNextFrameTimer = timeSetEvent( delay,
                                          1,
                                          reinterpret_cast<
LPTIMECALLBACK >( hSendNextFrame ),
                                          NULL,
                                          TIME_PERIODIC |
TIME_CALLBACK_EVENT_SET );

while( TRUE ) {
    if( sendto( address, data ) < 0 ) {
        //error condition
    }

    ::WaitForSingleObject( hSendNextFrame, delay + 100 );
}

timeKillEvent( mmNextFrameTime );
CloseHandle( hSendNextFrame );