AVR-Chat

hi.
I have some problem with my printer port(I think so).
becouse when I programed my AVR chip for the second time i couldent 
program it again.
(in the condition that i wase made no chenges in my softwar & hardwar.)
the error seys that byte0=FFh byte1=FFh byte2=FFh  and it must be ... .
afte I installed the new windows I could program my chip just for 1 
more time & the error came back.
& now i dont know what to do.