INT 15 - DESQview v2.50+ - SEND MESSAGE WITH ERROR RECOVERY
        AH = 12h
        BH = 80h
Note:   this function is identical to AH=12h/BH=00h, except that DESQview will
          not pop up a "Programming Error" window, instead returning an error
          code in AL:
                00h no error
                01h invalid values
                02h alias invalid
                03h handle valid but wrong type
                04h invalid handle