Serial transfer problem

I am using a DS89C440 flash micro running at 29.491Mhz with 64k of external
RAM and no external ROM.
I am running my serial port using timer-1 for baud rate generator at
19200baud.
My source computer is a P4-3Ghz running winxp-pro and my program for sending
data to the micro is Visual C++ 6.0
For some reason I dont under stand, not all the data I send to the micro
gets there.
My serial receive code for the micro is below:
;
; ***** Get job data from PC *****
;
  getpc: mov   dptr,#1000h            ;set dptr to data area
 getpc1: jnb   ri,getpc1
          mov   a,sbuf                 ;get char from port
          clr   ri
          movx  @dptr,a                ;save data to memory
          inc   dptr
          mov   a,dph
          cjne  a,#20h,getpc1          ;receive 8319 bytes
          mov   a,dpl
          cjne  a,#7fh,getpc1
          ljmp  loop                     ;top of program

Any ideas???