AVR-Chat

Does anybody use AVRdude software?  I installed it and tried to 
program an ATmega16 using a PPI programmer.  But AVRdude shows the 
following error message: 

  avrdude: AVR device not responding
  avrdude: initialization failed, rc=-1
           Double check connections and try again, or use -F to   
override
           this check.


I checked all the connections and they seems ok.  Since this is my 
first AVR board I have no clue about the cause of this failure.

Regards,
Jose