I know, it is a silly question, but did you "Burn Bootloader" for the ATTiny setup you want? There is no actual bootloader, but it will set the fuses and such. I have only done this once with an ATTiny, but I remember running at 5 MHz (4.8 actual) range internal.
If none of those work, I will setup a "Tiny Project" and see how that library behaves.