Ignoring the warning you got (that always comes up when signal.h is used) the errors are saying that the various registers are not named correctly.
This means either
(a) the library was written for an arduino with an AtMega168 chip and you are using an arduino with an AtMega8 chip
or
(B) the library was written for an arduino with an AtMega8 chip and you are using an arduino with an AtMega168 chip
You can either go through the datasheets for the chips and correct the register names (not that hard, and you'll have a better understanding of what goes on in that black bit of plastic) or you can swap what chip you are using.