Thanks for making, this it's awesome!
With regards to the error above, the offending line is the "sbiw %0, 0x01 \n\t". I'm messing around with alternatives, I found some place that suggests manually moving %0 into a register before calling sbiw which I'll try soon.
edit: 64bit linux, GCC 4.4.2, avr-gcc 4.4.1. I don't know what I'm doing so I gave up on my mov r30, %0 and sbiw r30, 0x01 idea.