Hello Rafa,
I think your avr-libc is too old. Check which version is installed using YaST. Add the repository http://download.opensuse.org/repositories/CrossToolchain:/avr/openSUSE_11.2/ in order to get the latest version. You may need to remove everything AVR-related using YaST and then reinstall everything after adding the repository. Don't forget to downgrade gcc to 4.3 again as YaST will want to bring in gcc 4.4. You won't need to recompile gcc if you haven't deleted the object files--just do a "sudo make install".
The Arduino environment can be a real pain under Linux compared to Windows, since the Windows package is self-contained. Let us know how it turns out.
David