try this:

	FUNCTION ProcessMessages
		This.MessageTimer.Enabled = .F.
		LogProcess( "Disable Timer" )

This is another solution not sure, because it is correlate with the time events sequence.

A sure correct solution is to simulate a atomic "test and set" into VFP.

 FUNCTION ProcessMessages
	IF <test and set>
	  	LogProcess( "Disable Timer" )
                ....
        ENDIF
....