[SOLVED] Set Low Fuse Bit, Now Can't Program over ISP

I now understand why your resonator isn't oscillating. I was reading the CLKSEL bits the wrong way round. You have your clock fuses set to low-frequency crystal oscillator mode, which is intended for a 32768Hz watch crystal. This may also explain why XTAL1 and XTAL2 are not behaving as I expected.

So it might be worth trying an even lower clock frequency.

Nick, do you know what is the maximum -B parameter that avrdude works with? Maybe -B250 is too high?