that would reset the program running in the attiny84 - but there isn't one is there?
No, there IS.
Thats the strange thing. I actually uploaded my sketch-code just fine using my Arduino-ISP and the core modification of the 0018 IDE.
And more than once for that matter.
After that... I can't remember what change I made and I get this error message.
I changed breadbords, for the bigger circuit, but other that that it seems the same to me.
(note that I get the same error using a USBtinyISP and avrdude, trying to just read the fuses.)
Could the reset pin be damaged (fuse set incorrectly.)
I just say that based on the fact that grounding the reset pin doesn't reset the code!