[BRLTTY] my computer is a stupid! brltty doesn't work any more

[Simone Dal Maso]

Hi Samuel,
a part an antivirus software, Free antivir, my system is clean.
this is a piece of log, thanks in advance for helping me.
C:\WINDOWS\system32\brltty -b md -d serial:com1 -l debug -n -e 
brltty.exe: checking for braille driver: md
brltty.exe: initializing braille driver: md -> serial:com1
brltty.exe: serial device opened: com1: fd=1828
brltty.exe: Skipping probable ACK packet
brltty.exe: ReadFile error 998: Accesso a posizione di memoria non valido.
brltty.exe: receive_rest(): short read count
brltty.exe: Invalid packet: STX 02, ETX aa
brltty.exe: braille driver initialization failed: md -> serial:com1
brltty.exe: braille driver not found
brltty.exe: Braille Display Dimensions: 1 row, 80 columns
brltty.exe: shifts: fwin=80 hwin=40 vwin=5
brltty.exe: checking braille device: serial:com1
brltty.exe: checking for braille driver: md
brltty.exe: initializing braille driver: md -> serial:com1
brltty.exe: serial device opened: com1: fd=1828
brltty.exe: Skipping probable ACK packet
brltty.exe: ReadFile error 998: Accesso a posizione di memoria non valido.
brltty.exe: receive_rest(): short read count
brltty.exe: Invalid packet: STX 02, ETX aa
brltty.exe: braille driver initialization failed: md -> serial:com1
brltty.exe: braille driver not found
brltty.exe: Braille Display Dimensions: 1 row, 80 columns
brltty.exe: shifts: fwin=80 hwin=40 vwin=5
C:\nvdasource\main\brltty-3.10-2\bin>