SurferTim, pert,
Thanks for your quick responses.
pert: with all due respect but I won't be posting the error messages. It will be pointless. I keep the verbose output during compilation on for at least a year now on my sketches as I do like to know what happens under the hood. I understand the errors I'm getting. I've been through both Wire libraries and can see how they differ. I just though there might be some clever stuff in the environment which I might broke in some silly way, you guys might know how to fix.
SurferTim: I suspected it should work like that. I've seen it working like that on other stuff. I sometimes move sketches and boards between my work and home computers (Windows) and laptop (Mac) and all usually works. Only recently (a few months now) it stopped on my home computer (unfortunately the main one).
I think Arduino on my home computer is long overdue for a cleanup. I'll try to do a clean installation with only these libraries I normally use. And before installing them all I will try do some experiments with the Wire lib. and both processors. We shall see... Then if still in dung, I'll post something more.
Thanks,
radoval