Vincent19:
What does the bolded part means ?
Locate the boards.txt file that came in the Arduino Tiny zip file. Open it. Change the .upload.using lines to something like this...
attiny85at16p.upload.using=arduino:USBasp
Save and close the file.
I did not do that.
With Arduino 1.0 and higher you may not need to. There is now a way to specify the programmer without editing boards.txt.